After his conversation with Balowski over the bomb, Mike suddenly has a wad of cash in his hand.
Although set in north London exteriors were filmed in Bristol. This is explicit here when a street sign for Codrington Road is clearly seen; the only Codrington Road in the UK is in Bristol.
The testcard remains unchanged as Rick hops channels and doesn't disappear when he turns the set off, all revealing it to be a dummy TV (later thrown around the studio).
When Vyvyan opens the cupboard to get a bowl and the plates fall off the shelf, you can see a wire fixed between the cupboard doors so that the wire pushes the plates off when the doors are opened.
After Rick leans on the bomb and it starts to tick, the boom mic is visible at the top of the screen in the center.