I apologise for not getting back to all with an update. Well that night i got home and went to listen for the fuel pump noise, couldn't hear anything.
But i thought i better make sure the situation hasn't got worse so i tried to start the bike, would you believe it after 2 days of nothing it starts without even a hicup!
Left it running for a few minutes to make sure it was going to tick over cleanly, it did. Turned the engine off and repeated the process, this time i heard the fuel pump whir (or whaterever you want to call the noise.

)
Engine started again cleanly.
I have now covered 300 miles since then, with multiple stops, to make sure the bike is starting correctly.
So, not sure what caused the problem, but at the moment it appears to be working as intended.
Thanks to everyone who gave advice and spent the time to write it in the forum. Much appreciated.
On a side note a letter came through saying that my fuel pump controller should be replaced by BMW as part of a recall, but not a safety recall. I'll pop into them and get that done and make sure it gets a clean bill of health before I leave with it.
Cheers all and have a free virtual pint.
