Took it to the main dealer in the end.
No idea how they managed to get into the vehicle in the end but they need to order some secret magic bits from germany to get in.
They admitted that the mechanical door lock actuators are flimsey and not meant to be used except in an emergency if your remote key fails.
So make sure you always have a spare remote unit and never rely on the mechanical key until you get round to (or can afford!) to get a replacement remote key/fob.
Have now sold the BMW 330D and crossed to the dark (three pointed star) side which so far has been utterly reliable and solid but not as exciting and fun as the 330D to drive/own. The whole experience just turned me so anti the brand.
So saying goodbye for the time until I get another mid life crisis and think about BMWs (and my memory has faded about hideously expensive door keys and cheapo crappy door locks! I assume the "engineer" who designed the door locks has been fired! Why ruin a perfectly good car with cheap penny pinching stupid cost down bean counter mentality!)