Thank-you everyone for your help. Just got the X5 back from the dealer and happy it was not anything major. They said Ignition, Airflow & Fuel pressure was fine, but the compression was low. They squirted oil in the cylinders and bingo it fired, they put it down to "stuck piston rings". I still think it had something to do with oil not getting to the vanos unit after I disconnected & reconnected the oil feed line, somehow putting the valve timing out enough to loose compression. Hope this might help someone in the future.