I have a wet patch of oil appearing between the fan base and back of the distributor and fuel pump.It pools in the tin ware around the pulley on the left side of the motor when looking at motor.
Any ideas?
if its the oil cooler seals,can the seals be done without dropping the motor??
Many thanks for any responses.

oil cooler and yes they can be but its best if you remove the engine lid a bugger with the springs but its the only way undo the the 2x 10 mm bolts at each end of shroud and the strap holding the genny
and lift if you are luckey you will be able to take the 4 x10mm bolts holding the fan on the shroud and than wrestle it off
good luck

turns out its a crack in the case , a very fine hairline beneath the oil sender..
Any ideas what i can do to seal the crack..

get a new case, sounds like the oil pressure switch was tightened in too much

The crack is well away from the thread hole of the idiot light sender.
its approx 20 mm or so beneath the sender unit and traveling downwards towards the oil pump.
Your right though , case is suitable for the trash..

get a new case is the only way to fix it