I'd certainly not recommend putting anything but day to day money into Turkish Lira at the moment. You need to see how both the economic and political issues settle over the coming weeks/months, with the resultant impact on the Turkish lira, which this morning has nearly reached 3.6 to the £. The fall in the Lira is obviously to your advantage, but I suspect that it will continue to fall until interest rates in Turkey are increased, which then becomes a further advantage to you once you do bring money across. So all good for you as I can see, but don't rush it, you could miss out on further economic advantage.
Good advice too from LeeGlo on putting all your eggs into one basket, in particular all into one currency, especially the TL.
Banking if you have enough savings to become an HSBC Premier Customer, you should look at opening one. Very good for all your banking needs, both in Turkey and the UK, and most of the services are free, including transfers between the accounts in different countries. Some times HSBC savings rates are not as high as other Turkish banks, although not enough, I believe, to outweigh the banking benefits.