I'm going to be visiting the British Isles next month and want to get cash here for airport tips etc?

The British Isles use pounds. Don't listen to anyone who says Euros are fine. Very few places in Britain accept Euros. Sometimes you'll see it in tourist shops, but it's not appropriate for tipping or for most travel expenses.

You'll probably get a better exchange rate if you just wait and get the money after you arrive in Britain. There are ATM machines in the airport. Also, tipping in Britiain is not like it is in the US. Cab drivers generally do get tipped-10% is fine. In restaurants with table service you should check to see if the restaurant says 'service is included' or 'service not included'. It often will say on the menu or the bill. If the restaurant is 'service not included' leave 10-15% for a tip.

The currency of Great Britain & Northern Ireland (i.e. England, Wales, Scotland, Northern Ireland, British Channel Islands) is the British pound. If visiting Scotland you may receive Scottish pound notes in your change -- it is preferable to use these notes in Scotland.

Euros.

Universal money accepted everywhere in U.K Stronger exchange rate than the pound...

pounds.