It’s not until you eyes age and make life more difficult that you appreciate how good you eyes were when you were younger
I now keep a cheap illuminated magnifying glass (okay, it has a plastic lens) on my bench, in addition to good lighting, so that I can see fine details.
Just a final update. New ULA 81 fitted in a socket from Charles at vRetro who I have to thank for getting the chip from New Zealand to the UK in under a week from ordering!!
I still have a few bits to do, check mic and ear sockets for correct operation, replace regulator with something more modern, some sort of bypass for the modulator and check the 16K pack I got with it but it now appears to be working as intended without the graphics corruption.
Once more thanks again to everyone who get me here with their suggestions and checks.
If doing further work, please do take precautions against static and make sure the board has been powered down for at least a couple of minutes before starting work. This is because the vLA81 is not as hardy as the old technology ULA.
Also be careful with the expansion port/edge-connector.
Standby alert 
