I'm loving the "Tall Person" approach to threads. It brings a bit of cheer to the mornings.
Perhaps however I should resist the response "High Dee, Hi"

Anyway, here's a few answers to your questions. Hopefully there will be other responses too.

1) Agree
2) Number plate. It'll probably be a square one.
3) Insurance. Here's a link:- What about insurance?
4) Wheel Lock :- Wheel Clamp
Hitch Lock:- Always a good idea especially with a small Eriba that can be easily pulled away. Many owners lock their Pucks to the house in some fashion when at home. Best wait until you get it home to see what type of tow hitch you have. Highly unlikely, but it might already have a hitch lock.
5) With towing mirrors, it's often wise to fit them if only to keep the local bobbies happy.
6) Probably two 7 pins but again, worth checking as it could well have been changed. If you can't find out you can purchase a suitable adaptor from places like Amazon, to tide you over.
7) It would be useful to check that the fridge and interior lights of the van work, either through the cars towing electrics or, if there was possibly a power supply to hand, by way of an electric hook up with a suitable British 13 amp plug adaptor. Beware, there is no running light for the fridge. The "on" light is just an indication that power is getting to the switch. Possibly take a gas bottle to check that the cooker works? Again it'll probably have a foreign screw on gas bottle adaptor rather than a push and twist Calor Gas type.
Randa

Just come across this Dee. New thread :- Hitch Locks.
Randa