Good lord, I used to watch this all the time. I'm surprised I still remember the hang up the brolly bit, but I remember Uncle Bobby.
To be honest, Bimbo freaked the hell out of me when he started to sing, but I couldn't stop staring at him. Mainly because I wanted to figure out what they heck he was saying. All I could ever get was "Bimbo" and "Happy Birthday" and the "Happy Birthday boys and girls" Everything else was just a mumble of random sounds.
Still have no idea what he was singing there, but I'm inclined to think he was chanting to some demonic power.