Interesting reading, thanks all.
John - see what you have done
though the microscope is not on the wish list
(yet)!
Jenny - thanks for the info on the Opticron it looks like the distortion will rule this out, this is possibly why it is only £15. I did find this supplier for the Oxford precision model which I think is the one John is talking about.
Cromwell Industrial Tools UK: PM 3010 LED POCKET MAGNIFIER : OXD-316-2010K
On offer at the moment for £30 (inc p&p) so reasonably priced.
Regards, JohnB