Mystery Oil Leak - Corsa 1.4 8v (X14SZ) - drawde
Oil is leaking out of my engine; leaving it overnight leaves a pool 3 to 6 inches across on the floor, and I can't work out where its coming from. The car's worth less than a mechanic's fees and I only need it to last 5 or 6 more months before I scrap it or (if I can) sell it.

Its a 1996 Corsa 1.4 8v (Hi-Torq), engine code is X14SZ. 150k miles. {Added to subject header so as to catch the eye of possible Vauxhall experts - DD}

Its definitely not the oil filter or the oil draining plug. I initially thought it was the "seam" that runs around the bottom of the sump, as this is very wet. There is not much wetness above this line however. I was informed by a mechanic friend (who lives too far away to look at it) that it is probably coming from above this seam, and pooling above it before running down and dripping off. He suggested I check the oil pressure warning light switch, but I can't work out where this is and the pic in the Haynes manual is no help whatsoever.

Does anyone know where this switch is, and are there any other common places for it to leak from?

Thanks!
Mystery Oil Leak - Corsa 1.4 8v (X14SZ) - injection doc
Would suggest a quick clean then lay under and watch for the oil! 1st guess is switch located near pump or oil pump gasket ( quite common!)
Regards