Just started my car up for the first time in a week to test my fuel pimp wiring (it worked rah!!) but i noticed a rather odd rattle coming from the rocker which was intermitent - almost like a rattle but not the normal tappet noise. Any ideas as to what this could be? It seemed to settle down a bit when left idling but as soon as i reved it, the noise came back. Any ideas?

Cheers,
Dan