Note that this drop is down to uncertainty in what will happen with the government and is probably quite temporary. Ratings agencies and financial firms have all said that it's unlikely that a hung parliament is going to affect the exchange rate in any appreciable way (though they can be wrong). Because of the potentially temporary nature of the drop, it's unlikely that a bank will offer you a very different rate than they would have done last week unless you have a very large amount to transfer - and even then you'd likely have to negotiate for the better rate.
Of course this isn't so much a problem if you're not transferring the money via a bank. There are various money transfer services that you'll find references to on these boards that may be worth looking into. I haven't used any personally, so I won't recommend anything, but there are certainly people here who will.
