When Mr. Bean visits the laundry, and plans his "revenge" on the "tough guy", we can see that he clearly pours up a mug of "Black coffee". In the next shot, it has milk in it. When "tough guy" accidentally pours it into the laundry machine, it's black again.
Mr Bean undoes his flies in the laundrette to get the extra pound coin, as he starts to put his stuff in the washing machine it is clear to see he has forgotten to do them up again but when he goes through all that business with Teddy they have been done up.
When Mr Bean is trying to remove the golf ball from a car's exhaust pipe, a man arrives and gets in the driver's side.
At the start of the scene, as Mr Bean approaches, the same man is already in the car waiting.
After swapping the cups in the laundromat, the level of the softener in the cup Mr. Bean is holding changes - it is higher as he goes to 'sip' it.
The top load washers in the Laundromat are listed as "large wash" and are the most expensive machines to use. Despite the tub depth, top load washers actually have the least usable capacity of any washing machine (due to space being taken up by the agitator), and thus, are generally the cheapest to use. The front load extractors (like the one Mr. Bean uses) would be the most expensive - they offer the most space.
In some shots, it is evident that the washing machine that Mr. Bean is using isn't filled up, or even loaded or moving while it's supposed to be on.
When Mr. Bean removes his underwear from the washing machine, you can tell that it isn't even damp.