Real bands cameoing as fictional bands in movies/TV?

There are several Slade Easter Eggs in The Grimleys.

I was referencing the rueful moment Noddy’s character Mr Neville Holder (itself an Easter Egg to Noddy’s real name) performs an acoustic version of Cum On Feel The Noize.

However you are correct there was a comedy version of Merry Xmas Everybody repurposed for Easter. Note this clip begins with Lewis Collins, the sadistic PE teacher in his Spitfire car. He was most famous for portraying Bodie in The Professionals. They had a great cast in The Grimleys.

TCMF-2L