£300+? It's a 960 replacement not the 970.
$239 release price for 4gb 960, nvidia added 40-50 on top of everything this time around (1070-1080) so expect around $279 release price which will put it around £270+ for 6gb or around £220/230 for 3gb with current rates in UK.
Not quite £300 but if you think it's going to be any cheaper than £250 then I guess you'll have as much luck as people who thought that the 480 will be matching 980ti and 1070.