If you don't change money until your holiday then I agree change the money in Icmeler, however the interbank rate is currently better now than it has been for two years, the biq question is will the interbank rate go down before your holidays.
Due to troubles in Gadaffi land the lira today has weakened, interbank rate now is 2.61 and I can get 2.51 at the moment, this will go up tomorrow, I'm expecting 2.52/2.54,
Tomorrow I'll watch closely and if the interbank rate drops I'm going to buy some and take the risk that it won't go up much further, if it goes up during the day I will check again on Friday, I always said once it 2.5 or higher I would buy some. I did the same a couple of years ago and got 2.48 in March/April, when I went on holiday in August it was 2.35-2.38 in Icmeler.
I have noticed that most years the lira get stronger the further into the season you go so you get less for the £, For those interested in seeing the fluctations below is a graph of Lira since 2002, I converted old lira by removing the millions, each months snap shot is taken on 23rd of each month.

I am not an expert in these matters so if you decide to do the same as me you do so at your own risk as the £ can continue going up.
Dave