As the bus crashes into the Cliff Richard billboard on the edge of the cliff, the driver's door is closed. But in the next shot, as it goes over the cliff, the door is open (so the stunt driver could jump out).
The bag of money the real robber is holding when he is held up by Rick is different to the one the manager was filling in the office.
When they crash their car into the lamp post and it topples down, the camera gets hit by it and jolts.
Vyvyan's cricket bat frequently wobbles when he hits things or people with it.
The "For Sale" sign outside the house advertises the address as "Carshalton" which is a suburb in South London. However the house has previously been established as being in North London.
During the bus trip, Neil mentions Basingstoke is 35 miles. Considering they are on single carriage roads, they must be on the A30. There are no cliffs of the size they drove over on the A30 between London and Basingstoke.
The bank-robbery is interrupted when the boys hear the voice of a policeman over megaphone, stating that the bank is surrounded. When they leave the bank with the money, the police are nowhere to be seen and the sirens are heard just a few minutes later, meaning they aren't even there yet.