Hi Terry,
I’m certainly no expert on copyright law, but if you are simply using a photograph as inspiration for a painting I can not see a problem – the image you produce is your work and your copyright. If you were reproducing the photograph (not your painting) in a book, or posting it on a website such as this, while the photograph was still within the copyright period, then there might be a problem.
There is some useful guidance at
https://www.gov.uk/government/publicati ... e-internetRegards,
Dennis
Regards, Dennis.