Morning, I've been looking around the forum this morning but can't find any similar questions and you seem like a friendly bunch so here goes

We have a '53 1.9 A3 Sport TDI which over the last week has started making a strange noise at the point where you turn the key and wait for the light to go out so you can start the engine.

Describing it is a bit tricky but it's like a buzzy warp sound, like an angry bee stuck in a jam jar (and i've checked there isn't one of those in the engine!) when you start the engine it either stops or you just can't hear it any more...

Has anyone experienced something similar or can you point us in the direction of where we might start looking for the problem?

Thanks in advance