wanted; spare wheel for Taskers pole trailer

[rustexpert]

I am looking for a spare wheel for my Taskers 6 Ton pole trailer.
They are 9 or 10 x20 tyre size eight stud three piece rims with "straight" centres i.e. no dish just a pressed rib around the circumference of the centre. The type for mounting singly that would be on various 1940/50's trailers.
I'm not desperate and something that needs a bit of repair wouldn't necessarily be a problem but wouldn't want to start repairing the one worst one I have without a fall back. A couple of tyres would be nice they are 16 ply heavy (10x20 on one axle and 9x20 on other but rims are the same) and would be difficult to dispose of otherwise.
On cleaning up they are stamped DUNLOP HO HA217. What does that stand for? Nothing relevant comes up straight away on google.
Anybody seen any? P.M. me if you can help..