Couple of pointers
- There is no such thing as no commission. Where there is non, it baked into the exchange rate spread
- London exchange bureaus which you find all over the place offers the worst rate.
- Stores that have exchange rate counters such as M&S, Tesco offer the best rates.
- As others have pointed out, never use your debit card, more expensive
- Pre-paid cash cards are worth the value.