Presumably Eileen Atkins (one of the originators of
Behind the Green Baize Door) will be available to appear in the show. IOTL she was appearing on stage as Queen Victoria (which coincidentally was the part Pauline Collins played in her second appearance on Dr Who).
So Pauline Collins keeps the role of Dawn on
The Liver Birds. That is going to have a major affect on the career of Nerys Hughs as it was her first major role, as well as being the one she is best remembered for. It's also going to have a large affect on the Liver Birds - it'll be like
Dr Who without Sarah Jane Smith
. Hopefully Mollie Sugden will be cast to play Dawn's mother (instead of Sandra's). Mrs Hutchinson was a great role for her - in some ways better than Mrs Slocombe - and in later seasons the dialogs between her and Carol's mother were often the high-point of an episode (IMHO, of course).
It's also going to have an affect on Pauline Collins' carreer. She obviously won't star in
Thomas & Sarah (a spin-off of
Upstairs, Downstairs), in fact this spin-off probably won't even exist. Also without her connection, her husband, John Alderton, won't join the cast of
Behind the Green Baize Door. Since neither of them will have worked for LWT, they probably won't be chosen to star in the sitcom
No, Honestly.
Cheers,
Nigel.