Hi Peter,
Stu and I opened our bank account last year when we purchased our apartment, we used Garanti in Fethiye, many of the staff there speak english.
We have just opened a savings account that pays 20% interest annually, it has to be a 'Turkish Lira' account for that amount of interest, but basically you can open sterling and TL cheque accounts and the same for the savings if you wish and just transfer from one to the other.
Just a word of caution though, probably best to deposit on a month to month basis in the savings TL account, just in case there should be a downturn in the market.
Hope this helps
Best wishes
June