Thanks Keith and Earlybird,
I normally replace that power/inverter board as there are plenty on FleaBay, and inverter tranny is always suspect.
In a slack moment, thought to check my pile of duff panels, and found that using the replacement 'D' version, the panels didn't fire up at all, whearas the non 'D' version provided secondary outputs.
Always use Wiltsgrove, although they're not too helpful on replacement RCU info, where you have to buy one to find the replacement code number, then might find you have a heap of 'em on the shelf.
Otherwise, not too useful as I can't get replacement inverter trannies, as they were supply deleted by ChasHyde a while ago. Note some info on Eastern European sites but.
Thanks again - Chris.
PS - Forgot to mention, tranny is 30052713