So, after weeks of problems it all, seemingly, came down to a faulty SD card - the one supplied by the retailer!
bought a new one, all seemed good. Then decided to clear the card in an attempt to rectify another issue - that of files being stored randomly on it .
A two day trip on the bike, time to see whats on the card.
Nothing! Just the words ”card removed”.
Yes it was, but its not now. I should have given up on this rubbish product months ago....