Thanks for even more helpful comments.
Changed the capacitor, it measured 220uf down from 470uf. Now doesnt get warm but I dont think thats the problem. I can make it display a 5 for overload if I hang onto the door while its moving. but my fault is 4 while its standing doing nothing.
Maybe quite a sophistcated unit with suspected pwm to slow the door as it's nearing the end stops. Think these are set as part of the installation if I remember correct. As its probably some microprocessor problem dont expect its easily fixable so another unit to try maybe a better option. Maybe manual operation is an easier option! This is a 550Nm unit, the ones on ebay are 1000Nm so probably quite old.
Thanks for the offer, shall I send a PM John?
Peter