I have has this same discussion about my motorbike on a biking forum. From what I have been told, a number plate has to conform by having the BS Standard number, and the location of where it was made.
BUT, if the plate is old (Ie, made BEFORE this ruling came into force) then this is not that case. My bikes and cars do not have these details on them, mainly because I get them made on on the interweb, and ask for daft comments instead, and they are all older then this ruling! None have failed the MOT on this.
Yes, if you get an over zealous MOT examiner they could fail you on this, but you could argue that the plate was made prior to this ruling, hence the lack of information.