Different colours on the number plate backgrounds to match the mounting place. What do you mean by 'bi-fuel'? Does 2010 mean a new-build date or when it was restored and rebuilt for gas fuel?

The number plate colours are standard UK colours. Bi fuel, and I have only learnt this since looking up the registration details for this van, means that it has twin fuel systems - petrol and gas - LPG I think. These are switchable so one can use either, but not at the same time. I guess it means that if you prefer to use gas for environmental reasons you use that, but there aren't as many LPG filling stations, so petrol is the fall-back fuel. There are other bi-fuel combinations.
2010 is the date this van was first registered. I don't know whether that was as a bi-fuel type. As this seems to be a newish fuel system, it could have been converted subsequently. It certainly looks like it has had a thorough make-over fairly recently.

Outstanding collage.

Nice collage.