Thank you. I can't remember how I installed wine or why. I never used it. I think I had problems installing from wherever, removed it (I thought) then installed from the package manger. Anyhow, I've removed it again (using package manager) & removed the repository you suggested. Updates now work
For anyone in the future who, like me, hasn't had to remove a repository before - I did it thus:
Open synaptic package manager (aka install/remove software)
select 'repositories' from the 'settings' menu on the top bar. (new window opens.)
The repository I wanted was in the 'other software' tab & already 'ticked'.
I highlighted said repository by clicking on it (whole line highlights) & the remove button (at the bottom) became active.
Clicked remove button.
new window opened with something like 'reload is required to finish'. clicked reload.
job done. quit package manager.
Thanks again.