Hornby Steam Scotsman - Loose Wheels then a Disastrous Derail

I ordered one of these models when they were first announced to be certain of getting one as they promised to be a big step forward in Model Railway Realism.
So, imagine my disappointment upon opening it to find that the Pony Truck wheels were loose, but no damage had been done so it was easily repairable.
However worse was to come, after setting up the Loco and completing a few test circuits with everything working fine the loco then derailed when crossing points and stopped working.
The pony Truck wheels hadn't moved and were still in the correct back to back setting but the decoder had just shut down completely so not one single function worked.
The decoder would not reprogram so now there is an expensive choice, do I risk buying another Bluetooth decoder for it or parcel it up and return it on my next trip back to the UK.