Gavin, I found it by doing a search on the net, I can't remember what it was called but I do remember you had to buy it and it wasn't worth me buying it for what I needed. We have always just used a block font for plates in the past something like ariel bold and we have never had any problems. You could scan the old plate and vectorise it if you had to. Shouldn't take more than a few mins to edit.
Hi Gav
If you look here; http://www.dvla.gov.uk/vehicles/regmark ... onalplates under ‘TRADITIONAL NUMBER PLATES’ you will find that it’s not necessary to use a particular font but it must be of the right dimensions, this goes back to when they were hand written.
You may find this interesting if you’re talking old;
It comes from the 31st edition of ‘The Motor Manual’ published in January 1941 price 3 shillings net.