Saw an article about this in the BMF Rider magazine. It’s a series of 3 hour endurance races. There is only one round this season at Anglesey on the 12th September. The interesting bit is the rules - only bikes built between 1990 and 2000 can enter. Also the sub-600cc class also allows twin cylinder bikes up to 905cc… Now let me think, who do we know who made twin cylinder bikes of 904cc in the 1990’s 
take a look at the web site athttp://www.nobudgetcup.co.uk