As the originator of this topic I thought I would advise all those interested that I am now receiving my private pension tax-free from the UK (backdated to the first payment in January). I applied to HM Revenue & Customs using the "DT/Individual" form, having gone through the process of having the completed form notarised first (Koray Atak can arrange this for 130TL).
My tax code is now "NT", and I assume that this will apply to my State Pension when I start receiving it in a few years time. As the personal allowance (i.e. the amount you can earn from pensions, interest, etc) for the 2011/2012 tax year is £7,475 for a single person, anything over this figure is taxable at 20%. Anyone with a decent private pension could benefit massively by applying for an NT code in this way. In my case, as far as I was aware I had already become ineligible for NHI benefits, and the saving I'm making will more than cover any health insurance costs that I might take out here in Turkey!
I would point out that to get such benefit the pension needs to be paid into a Turkish bank account - I have it paid directly into my £ sterling account (so I can take advantage of any exchange fluctuations!), and it costs me only £2.73 for each monthly receipt.
