Schroff87 - thanks for the info. TBH, I only really do cleanups now and again and not regularly as I may have suggested and I do believe this to be good practice but I am aware this can give side effects so maybe I should limit this to if/ when a problem arises. I just did a fresh install and that seems to be OK for now but I will look at the profile manager comments you have made.
Thanks to all who replied - don't know what I did before joining this forum, the knowledge out there is frightening.....