animation name???

[plastic_forks]

Hi I joined this forum to find out the answer to one question - can you help?

When I was younger I watched an animation on BBC2 around 1985/1987 – it featured a young boy who travelled aboard a spaceship and went to a planet where he was attacked by a flock of strange birds which tried to eat his brains. He was saved by an old man who lived on the planet, he had a bed with fish in it, and at the end of the animation it was revealed that the young boy was the old man (he had a metal plate where the bird had attacked him).

Possibly french?

Does anyone know what this was called or have any information about it? As a kid I found it pretty disturbing and only every found one other person who had seen it, but they could remember what it was either, can you?