We always check the rates on
http://travelmoney.moneysavingexpert.co ... y/#resultsThe rate for the post office though is lower if you don't order online. We've used ice and they're excellent. As well as this website we also check asda but their rate is different in store. For M&S, it's the same in store for Lira but not for some other currencies eg. euros. Another one suggested on this forum is travelfx. We've avoided them in the past because you have to do a bank
transfer and we thought that there would be charges. Someone else mentioned on the forum that there's no charge for the bank transfer and you can also get them through Lloyd's bank. Not quite sure how this works but if there's no charge their rate is better than the others most of the time so it's worth considering.