Neil Harris writes in to say: buying foreign currency from a high street bank or travel agency either involves a hefty commission or a poor rate of exchange. I’ve found the best rates for popular currencies are to be found in Oxford Street. On the way to the last Globetrotters meeting I got $1.85 to the pound at the KM Cash Booth that sits at the end of a souvenir shop at 53 Oxford Street. At the time the Post office were offering around $1.78. Both are commission free. I have used this exchange many times and trust them, there are similar exchanges nearby. I believe these prices are a reflection of the poor exchange rates that they can obtain through a bank.