Thanks to reading other 75 owners' problems with starting and taking the advice of the solution possibly being a new camshaft sensor, I was able to tell my 'Rover' dealer (now a Ford garage) in advance and they had the sensor on stand-by when I visited today for an urgent diagnostic check. I'd begun to call-out the AA on consecutive days with the non-starting problem, both frustrating and a tad embarassing. Hurrah, the diagnostic check kept coming back to the camshaft sensor being the culprit. Thanks for all the help.