It was from Peter's Christmas special, which was on twice. The second time was on rather late and there were extra sketches, but the beeb didn't advertise the fact.
This is one of the extras too, I'm trying upload a few but it's taking bloody ages.
(, Sun 28 Dec 2008, 11:58, Reply)
Still not seen Wallace and Gromit yet...
(, Sun 28 Dec 2008, 13:24, Reply)