Thanks all, well surprise, surprise ...... took the bike in for the first service and mentioned the surging and handed over the 2 print outs linked by the Cap. They were also due to replace a scuffed fork leg under warranty.
On collecting the bike, the fork leg hadn't been fitted because 'Yamaha had sent a black one instead of silver' and the surging "was due to the TPS recall" but they couldn't fit it as they hadn't got the part.
Despite me pointing out the contents of the print outs at reception I doubt that the 'mechanic(s)' even looked at them.
The outcome? another 110 mile round trip to get the fork leg and TPS fitted. USELESS
Remain unconvinced that this will cure the surging - update to follow!