Nick Grey wrote: What benefits/costs will there be for those ECF represents?
Provided the current VAT threshold isn't drastically reduced, most chess organisations have a turnover well below that threshold. Two that don't are the ECF itself and the UK Chess Challenge. So, subject to being within whatever the rules for exemption became, these two organisations or those who finance them would benefit.
The Contract Bridge world in the UK is organised on a far more centralised basis than the chess world, such that whilst entry fees to a typical UK event wouldn't attract VAT, those to a similar Bridge event probably would.