Just as an update, I've been playing with an Excel spreadsheet comparing typical hire costs with various shares that are currently for sale.
If anyone wants a copy then PM me your address and I'll forward it over, but it seems that for most 'typical' GA aircraft the hire v buy cross over point is circa 25 hrs per annum with no appreciable saving in costs in ownership unless you do more than that.
So it looks like the 'fly, float & F...' rule holds true, although willing to be proved wrong in all!
FA