Unless nV come out and say the 3000 series is going to be cheaper (have they?) then I think we're safe adding £100 to all the 2000 series prices.Imo its too little too late, by the time its released Turing will be 2 years old and Ampere will be here, so unless it has dramatically more performance than the 2080ti (30%+ minimum) at way cheaper prices I cant see how they will compete with the 3070/3080.
Just matching the performance of the 2080ti at £800-900 or whatever wont cut it when the 3070 will most likely be very close to the 2080ti for £500 (or £600 knowing nvidia)
A 3070 for £600 seems about "right".