My wife and I will begin a "A Week In...Scotland" tour next month, followed right after by "The Best of Ireland, Small Groups" tour. Upon arrival in Glasgow, Scotland we'd like to exchange some US currency to pounds and euros, respectively. We've read that the airport exchange rate is terrible (as is often the case), and that post offices or Tesco stores are far better. Anyone feel a want or need to exchange US currency during your travels? If so, where would you recommend for the best exchange rates?