I can get the S7 for an extra £110, are there any significant benefits in relation to the Gear VR despite a marginal increase in graphical performance?
Overall performance will be much better on the S7, plus you have better cooling and a better battery, so your phone won't die out as soon while playing VR content or stop because the unit got too hot (some games have been known to heat up the S7 variants after a prolonged session, it just won't happen as often as it would on the 6).
The Note 5 and S6 have more overheating issues, but you still can do well in a cool room or with a fan. Some people have even taken to making 3D printed covers with cooling fans and batteries built in.