With repect, without pics or info it's just a guessing game. You don't even quote the HP or cc.
Has the "racer" got any provenance? Still in racing trim? :-/
I would take a wild guess a say probably £10,000 the pair but if it's not a "real" racer then that could decrease considerably.
But if it's got evidence of someone famous having ridden it, the price will rise too.
Just about impossible to say.....