I have finally managed to top-up my Turkish pay-as-you-go mobile from the UK, and hope that this may help others.
I have a YTL account with Finansbank, and I have Internet Banking enabled. I guess many of you will also have this.
Under the "Payments" section of their on-line banking is the facility to "Top-up", and Turkcell Kontours is one of the options.
However, the system will tell you that you will need an SMS Password from their High Security Menu.
What you will need to do, is register a UK Mobile with them, which you can do on-line, but you are going to have to telephone them anyway - this is the number for their internet banking: 0090 212 4440900 Option 9.
Once you have registered your UK Mobile, you can request the top-up from within their on-line banking system, and at the point where a screen pops up asking for the SMS Password, you will receive a text from Finansbank with a four digit code which you simply enter on-line, and Hey Presto, you have topped-up.
I got the confirmation text from Turkcell within two minutes and my balance had increased accordingly.
Next time you need to top-up, you will get another SMS Password texted to your UK Mobile as there is a new passwprd for each transaction.
I hope this helps some of you, because if you are like me, you must hate that first day visit to buy a new SIM card - it is such a waste of time and seems to take forever - and then you have to text all your important family & Friends with your new number. Hopefully this should solve that problem.
Good luck.
Dave Nicholson