This problem is now fully resolved!!
Dropped the box out (boy are they heavy!) spun plate, checked starter, box back in with filter change and superb. It's never sounded better when it turns over and starts. Actually sounds smooth and engages properly with the flexiplate. One happy bunny!
Cheers for all the suggestions, I should really question the previous owners work by now. Even the filter in the box had the washers etc on the bolt wrongly placed to the filter would wobble about and was hitting the bottom of the pan!
Onto the next problem.............new thread for that!