Best way to invest a few grand

Hi

Both myself and the girlfriend have a joint Santander bank account with a few thousand pounds in it of our savings. The interest rate is down to a pathetic 0.10%. I have had ISAs in the past but need the money in an account that is easy to access (from cash machines etc) in an emergency but is going to give me better interest than the above. This is not our main account that our wages etc are paid into so the only money going in will be the odd topup from me or my other half. Anyone any ideas?