Almost impossible that you will get a fine, more like a producer.
Carrying a spare set of totally legal plates will get you out of trouble and make it not worth the police doing the paperwork if you ever do get pulled.
Anyway, I blame the DVLA, they are selling these numbers with the clear intention of them being illegally spaced - loads of them dont mean anything at all unless you space them wrongly, yet all the best ones that will look good when they are illegal are strangely enough, much more expensive than the rest. Then they try and weasel out of it with their disclaimer.
Just go for it.