Does any one know how? i have a sender unit which i think needs to be in place of the oil pressure switch which i cant find, also will i need a t-piece for it ?

 

If you want to keep your existing oil pressure warning light working then you will need a T piece, otherwise no you don't, I'd keep the oil ights as well personally.
Not sure on the zetec se but on silver top is at rear of block undeneath alternator area from memory, only thing like it on the block really, just make sure you get the correct fitting t piece, pressure ones are normally 1/4NPT-18.
tabetha