Hi Brian
It's many years since I researched the Rees family and your email was a most welcome surprise. The Rees family is the maternal line of my late wife and Richard Montaguie Rees (1844-1918) was her great-great-grandfather. Nearer to home her grandfather was Elyder George Rees (1880-1927) who married Jane Ellen Ellis (1881-1941). My research found seven children, which includes (your) George Rees and his sister, Dorothy, my late wife's mother. My research traces a Rees family tree to the 1600s and back in time to the early formation of the Rees family in Wales. Cilymaenllwyd has a fascinating history and I have a CD 'Cilymaenllwyd - 'From Gentry Home to Nursing Home' by William and Benita Rees (equivalent of about 800, A4 pages) issued in 2009. Far too much to publish on this site but I'm here to help.
Do get in touch if I can help but I think any next exchanges might best be through private e-mails.
Regards
Gerry