[jstanley]

It is easy to purchase a number plate for whatever text you like, e.g. https://www.myshowplates.com/

I find this type of thing the easiest place to purchase number plates because they don't make you jump through a load of hoops with sending copies of the V5.

[oliwarner]

I did say legally. The Road Safety Act 2006 requires suppliers of number plates to be registered and, looking at the law, I see no provision for the sale of "things that look like number plates but they're really not, honest guv".

UK statute is painful to read and interpret though. I may have missed something.

[jstanley]

You implied that the illegality of purchasing such a plate rested on the customer. I think it is perfectly legal to purchase such a plate, it's just not legal to sell one.