Thanks for taking the time to read and reply to my post Joe.
I have just run the mower for around 10-15 minutes mowing a small section of lawn and all is good - oil is showing just above the full mark and there was only a small amount of smoke when I had finished.
I'll put it to work again, probably on Sunday, and then look into the inlet manifold gasket whi0el the grass is growing again!!!
Peter