What is the law about my subject. I like many others have the letters and numbers hand painted, in my case in white with a body colour of dark red on the supercharger cover. I saw some details on the Gov website about white on black plates, but not that clear for our age of cars. I seem to remember someone saying pre 1937 cars were exempt, but that may be hearsay ?
My J2 has had the registration number displayed in this way since the mid 50s, first white letters on dark green apron, then white on black since the mid 70s. It has never been a problem with either MoT or the boys in blue (even when the latter were lecturing on displaying a tax disc - they didn't like folding windscreens & recommended the motorcycle type holder, nearside so visible from the kerb).
I wouldnt worry about this, I shouldnt think any Mr Plod would know anything about this. A friend with a TC has very nice numbers & letters cut out of alluminium sheet, they have been on his car 52 years. Cheers, Nick