So, I finally gave in as I was wasting so much time on this. Sent to Darkframe - got it back in 3 weeks ...
Had a fair old crack with it last night trying different settings ( 1 to 3 seconds guide images, EQmod guide rates etc)
Settled on 3 seconds PHD2, binned guide cam (ZWO 290 mm) 0.5 guide rate in EQmod and followed guide assisitant recommendations.
Had good spells below 1 arc minute, still having occasional spikes but so much better than previous attempts.
Logs attached in case anyone sees any room for improvement. Also a wee Horsehead, about 45 mins of 300 second Ha s