Problem has been solved - key bindings from a previous aircraft configuration in the throttle quadrant - fuel bindings. Strange thing is - no switches or in this case the fuel valve levers were affected - they all stayed where they should be.
I therefore have to retract the statement that the DA62 is not working - you’ll forgive me for thinking it wasn’t having found a previous topic that for all the world replicated my problem.
Removing all the fuel settings on the Brava configuration allowed the engine start process to go ahead normally. I even managed to configure the two engine master switches to the Bravo which given the nature of the Bravo and it’s switch behaviour is quite something, If I could only configure the fuel selector levers…
All is well with the world with this aircraft now. Thank you - firstly for ensuring that I was following the right process and secondly for the binding solution that was in fact the unexpected root of the problem!