While on a motorway or dual carriagway, when i have passed a LGV, the driver will flash me in, which is very polite , but if i was to move over to the left when they flash me i will be on a collision course with a car/truck that is merging out to join the road on the slip road.
When i stay in the lane and do not go over, i see them flashing their lights at me in annoyance, and have not worked out what i was doing, as anyone else had the same thing happen to them.
I don’t flash and I ignore them that flash me.
The reason being someone flashed me in years ago and clipped a car.
Never again.
I dont flash in near a slip road and leave the driver ahead to check and make their own decision to move over when they decide it’s safe. If they flash me in I’ll acknowledge with indicator flash to let them know I have seen their headlights and move when I decide it’s safe to do so.
If they get the asre it’s down to them 
Whats more annoying is when you join a motorway running out the slip to its full length and some zb in a car drives straight on and then sits there flashing for you to pull out.
If someone flashes and I’m planning to stay out for whatever reason, be it a sliproad or to keep going passed the next truck, I usually just give 3 flashes right, says I’ve seen them but I’m staying put.
Personally when being passed I wouldn’t flash in range of a junction for that very reason, and also there’s a risk that the person joining the motorway and the truck in the second lane responded and would end up in a mess in the middle.
Very good point.I have noticed this many times.It is worse on normal roads though.So many drivers flash their lights thinking they are helping another driver when in actual fact they are putting others in danger.(sometimes pedestrians and cyclists)
A lot just dont assess the situation first.
Flashing lights means one thing and one thing only to let other road users know you are there as most probably know(or do they)
I agree with the right hand ind flash, To me it means thanks but im ok here mate…
dew:
If someone flashes and I’m planning to stay out for whatever reason, be it a sliproad or to keep going passed the next truck, I usually just give 3 flashes right, says I’ve seen them but I’m staying put.
I’d just give the standard indicator thank you in that situation. Giving 3 flashes right may confuse the Audi driver bearing down on you in the outside lane at 130mph, causing him to panic, lose control and then flip onto the opposite carriageway and into the path of a coach full of school children on their way to the seaside. 
Contraflow:
dew:
If someone flashes and I’m planning to stay out for whatever reason, be it a sliproad or to keep going passed the next truck, I usually just give 3 flashes right, says I’ve seen them but I’m staying put.I’d just give the standard indicator thank you in that situation. Giving 3 flashes right may confuse the Audi driver bearing down on you in the outside lane at 130mph, causing him to panic, lose control and then flip onto the opposite carriageway and into the path of a coach full of school children on their way to the seaside.
Trick shot 
countykev:
I dont flash in near a slip road and leave the driver ahead to check and make their own decision to move over when they decide it’s safe. If they flash me in I’ll acknowledge with indicator flash to let them know I have seen their headlights and move when I decide it’s safe to do so.
If they get the asre it’s down to them
I do exactly the same I think it’s good practise this way cause its Sod’s law ill flash them in just as some ■■■■ comes flying up the inside to the end off the slip road and swerves into the side off it.what annoys me Is when a driver overtakes me and pulls straight in infront off me though this is starting to happen more and more regularly the reason a set cruise control at 53 is I don’t want to constantly be up the arse off lorrys getting stone chips all over the front then you get some nob who pulls straight back infront and gives you a couple ill start sending a paint bill in a minute(rant over apologise for that got carried away)
toby1234abc:
While on a motorway or dual carriagway, when i have passed a LGV, the driver will flash me in, which is very polite , but if i was to move over to the left when they flash me i will be on a collision course with a car/truck that is merging out to join the road on the slip road.
When i stay in the lane and do not go over, i see them flashing their lights at me in annoyance, and have not worked out what i was doing, as anyone else had the same thing happen to them.
It happened to me in my early years of driving, I nearly hit a van that came down the sliproad. So i don’t pull in near sliproads and i don’t flash people in at them either. It’s polite to flash people in, But it’s sometimes safer not to.
Contraflow:
dew:
If someone flashes and I’m planning to stay out for whatever reason, be it a sliproad or to keep going passed the next truck, I usually just give 3 flashes right, says I’ve seen them but I’m staying put.I’d just give the standard indicator thank you in that situation. Giving 3 flashes right may confuse the Audi driver bearing down on you in the outside lane at 130mph, causing him to panic, lose control and then flip onto the opposite carriageway and into the path of a coach full of school children on their way to the seaside.
You forgot to mention so called professional drivers. 8/10
Hiya the flashing in thing come about before 1960 with night driving lorries. before 1960 their was no
mirrors on the nearside, so in the night the slower lorry would turn off and back on his lights, this
could be seen on the road surface and the faster lorry new it was clear to pull back on his own side
of the road. alot of things to be take in on these occasions, less traffic…slower lorries…not many
dual carrageway’s…no motorways…no street lights out of towns(everywhere very dark)no sliproad’s
and not many cars
john
Contraflow:
dew:
If someone flashes and I’m planning to stay out for whatever reason, be it a sliproad or to keep going passed the next truck, I usually just give 3 flashes right, says I’ve seen them but I’m staying put.I’d just give the standard indicator thank you in that situation. Giving 3 flashes right may confuse the Audi driver bearing down on you in the outside lane at 130mph, causing him to panic, lose control and then flip onto the opposite carriageway and into the path of a coach full of school children on their way to the seaside.
as long as he is liable i dont see the problem 
I wouldnt pretend to know too much but i wouldnt flash anyone in unless they were indicating to do so and when overtaking i judge when i am past (my truck must of had slicks on for calibration )then indicate and wait for a flash, or not 
grumbo:
I agree with the right hand ind flash, To me it means thanks but im ok here mate…
One tick…s’what I do too.