Water Leak....Help Needed Pls.

[Pal318is]

Guys,

I've just had the car mot'd on friday, with the new engine in and other bits and bobs. However after sailing through the mot, it's now developed a water leak from around the profile gasket(brand new)/thermostat housing. I've just taken the whole thing apart and sealed it with some sealant, but this has not helped..!
It's definately leaking from around that area and then dripping onto the cam sensor...i can't get my head around it.

My mate at my local dealership, said that the water may well be coming from an overflow hole of some sort?? As he intially thought that the water pump was fooked, but this has been replaced too, albeit with one from my brothers car, which is definately working.

Before i forget, the engine is not overheating, probably due to me topping up the water..

ANY help would be much appreciated...

Thanks

Pal