Firstly, good morning and welcome from the UK!
My heart really goes out to you. Even bringing a new puppy home, it takes time for them to get over the trauma of leaving their mum/litter mates/familiar surroundings. So after 8 years.....Personally I think again it is time and patience and coaxing.
I know others may not agree, but have you tried mixing some chicken breast in with her food? I think at this stage I would be doing anything I could to try to entice her to eat
Please don't lose heart, it will all come good - eventually. Sally + Harry x