Ok guys, thanks for all the useful input, decisions made so far;
Radio- existing 14MZ/ rx 14 channel 6014, Powerbox sensor switch with 2 x 2100Lipo, electric retracts ( can I run these off the 2x Lipos?)
Model IAD Model Designs Serpent - 77 inch span looks like Kingcat clone CNC built up kit with glassfibre fuselage ( I have plenty of time to build!) suitable 60 -100 turbine.
Turbine - waiting on input, liking the Kingtech 85 or Xicoy 70 - any views.
John