My all time favourite has to be 'The Hotel Inspectors'. Brilliantly written as were all episodes. This was one of those episodes where we really got to see just how awful and rude Basil could be. For me Mr Hutchinson played brilliantly by Bernard Cribbins stole the show with his performance.
The funniest moment for me was when Basil was attempting to restrain Mr Hutchinson's complaining by laughing out very loudly and covering his mouth with his hand, and then giving him a knock on the back of his head and causing him to fall face-first into his dinner.
Also must give James Cossins a mention, he was also very good too.