One aspect to consider is that Sterling has been falling in value lately. Some might say that there is something in the prospects that is leading to this slide downward and you night want to investigate that (perhaps look for recent analysis). The prospect of the UK leaving the EU may well be that reason, in which case Sterling might fall further in value if a No vote is considered likely. The lower it falls, the more Pounds you would get as you wait it out, the difference in value over the past few weeks is edging toward 19%. On the other hand if the value rises you would lose out - you are unlikely to find anyone prepared to promise/guarantee anything regarding the future, it is in reality a gamble but you at least know the recent history. If you think a Yes vote is becoming likely then you might want to exchange now, otherwise it may be prudent to wait to see how things develop. The method of exchange is something I cannot advise on except that there will be more than one option.