Thanks for the tip. Will give it a try.

I do seem to have solved the problem over recent visits to the range. As mentioned, I was hitting my irons consistently but had trouble with the driver (and other woods). My problem, I think, was treating the driver differently from the irons and changing my swing when I was trying to use it. I realised that I needed to use the same swing with the driver as I did with the irons. What I did to solve the problem when using the driver was to imagine that I was using an iron - this helped me get over the the 'mental' problem of having the driver in my hand. This has produced excellent results.