There is an ATM in the Disney village just to the side of Hurricanes nightclub and next to the ticket booking office for Buffalo Bill.
There is one at the railway station.
The only hotel that has one is the Newport Bay and its near the convention centre.
In the Studios there is one on the front lot as you enter and also one near the Backlot restaurant.
In the main park there is one in either of the arcades that run parallel with Main Street.
There is one near the Buzz ride and also one somewhere in Adventureland but
Most UK banks charge a withdrawal fee when using an ATM and a handling fee for using your card abroad - this is usually around £1.50 or 1.5% of the transaction.
There are also places to change money if you take currency with you. Be sure to keep it secure if you are taking a lot of cash with you.