David,
The problem with tyres is that although many sizes with correct treads were manufactured long after WW2, recently it seems they all have been discontinued. NOS tyres are often well over half a century old - not really fit for road use.
Followed up that link you provided, and indeed found their list impressive - it even includes those 10.50-16 Coker "Firestone" chevron tyres I asked Tony about
:
Tony will probably tell us now that although Antique Tyres lists these tyres on their site, they no longer stock them.
The same is true for
http://www.olympictyres.co.uk/, they do list the 9.00-13 Grassland tyre on their site, but no longer stock them.
In the end one of us will have to order a batch of 1,000 or so and sell them to other collectors at 4 at a time....
Hanno