EZYramper...
Not sure what it is like at easyJet but at the airline I went to (don't let my screen name fool you though!) it's not as straight forward as £1000 cash in an envelope to give back to HSBC. There are all kinds of interest and tax implications that go in the most round a bout way which really need some understanding.
Unfortunatly, you won't know these details until you join your airline.
M330