Well yesterday I bought a new OEM carb rubber marked 94 on the top for my R model, installed in the rubber was a metal washer, lo and behold this washer (now removed) was the same size as these I already have.
So I can now confirm these washers are NOT the 33bhp but the 53bhp restrictors. So who ever is selling a look alike set on ebay as 33bhp, sorry there not.
The offending washers:
