orys:
Other thing is that I have B+C licence valid to the end of my live (no expiry period). Off course to be a proffesional driver I need some medicals, but that goes to my polish CPC (which I don’t have, as I don’t need it to work in UK - here we have another loophole, you can be a lorry driver in UK with only basic medical examination) so even If I won’t be able to drive a lorry for live I will still be able to drive for example an 18t camper when I will be old.
But in Britain there is no such thing like driving license without expiry date. So if I will exchange my license to British one they’ll give me one valid for 10 years or whatever is the longest period here. Then, when I come back to Poland, they won’t just give me back my old license, but they will exchange my British one to Polish one with the same expiry date… And then I would have to do medicals periodically…
So staying on my polish license saves me a lot of hassle.
I’m curious - what’s a B+C licence

I don’t know how the Polish system works but I can tell you what happens with the UK one 
A ‘B’ (car) licence is valid until age 70.
At 70 the driver is required to have a note from their doctor to say that they are still fit to drive. This is a very minor fitness check and not a full medical like the one for LGV or PCV.
Now, this is interesting -
If you did the ‘B’ (car) test before 1997 the driver got D1 (102 code) and C1 put on their licence.
To retain D1 (102 code) and C1 after the age of 70, a FULL medical must be passed using the D4 form which is the same medical as for LGV & PCV.
B+E entitlement is not affected
For those that passed their ‘B’ (car) test after 1997 and then passed ‘UPGRADES’ things are a little different -
Every upgrade has an expiry date which is usually the date when a medical is due in order to use it.
If the medical is not passed then the upgrade is not valid.
As many have found out, letting the medical lapse does not mean that they have to take a DSA retest if they wish to start using it again - they just have to pass a D4 medical.
B+E entitlement is not affected
I keep mentioning that ‘B+E entitlement is not affected’ and there is a reason for this -
If the B+E was gained as part of ‘upgrading’ by passing any of the ‘+E’ tests then the B+E is not ‘lost’ if the upgade is not valid.
Example -
Pass B in 1999 - no extras given
Pass C in 2001 - now get C1 added
Pass C+E in 2002 - now get C1+E & B+E added
Let medical lapse at any age over 45 - lose right to drive C+E, C, C1 & C1+E but retain B+E.
This has been done this way so that a former +E driver can still tow a large caravan etc in retirement.
