Hi Gaz. Reversing: dont be afraid to take a shunt - or two. If you shunt, make it count. You can, as you know, go all the way forward to the end of the reversing area. If there’s any chance of the trailer or unit getting too close to the left hand perimeter line (the one in front of the workshop), go forward. Imagine your car is parked there and figure out if you’d go forward or just risk it!
In the rain: you already know this. But double your separation distance between you and the vehicle ahead. Work a bit harder on the approach to green traffic lights - - if they change it’ll take longer to stop.
All the very best with it; stay cool and you’ll be fine.
Pete 