A good point Will. You and many others have probably been subject to the PRMC finance lecture, supposedly independent financial advice where they try to convince everyone it's a good idea to join Barclays as there's a branch in Lympstone. (Lloyds do the same at Raleigh). By good chance they bring along a load of application forms "just in case". Spooky, I wonder if there's any for HSBC in amongst them?
The simple fact is that you DO NOT have to join Barclays if you're happy with the bank you are already with. All you need is your cashpoint card & the machine is free to use unless your own bank state they will charge you. (Most currently don't)
It rather annoys me that these banks try to sell their services to new joiners some of whom may possibly think they must join a particular bank. I've heard relate of horror tales of "If your wages don't get paid in, we can help you" or "If you're feeling down, come and have a cup of tea with us". It's simply a sales pitch- there's nothing wrong with Barclays or Lloyds for that matter, but any reputable bank would do the same- it's down to he individual to choose with whom they bank.
My advice, if you already have an account, you think it's OK, then don't bother changing. Otherwise Barclays will sort you out when you arrive, fear not- they're good at it as they get around 20+ new accounts per fortnight.