Thanks Raron,

First thing charged the batteries after the servos glittered. Batteries are new Liion 3000mah from emcotec, no luck.
Just for test used a 7ch spectrum RX with a PB sensor switch, eventually a PB Mercury will be used.
Thought initially the servo leads may be a bit long, but simulated similar length direct to the Rx bypassing the 8pin connector and all is fine.
servos are JR 8911 and 8511.
scratching my head on this one.