Im thinking of a cable....

Sie

....but for the life of me I cant think what to call it to search on google for where to buy one.

What I used to have was what I would call a pass-through power cable.

IE: The monitor cable has a female AND male connections on the end. One to plug directly into the PSU and one to allow the cable from the mains to plug into this. Thus allowing both to be powered from one mains power cable.

Any idea what they are called :

(I may locate the old one i had from home later on so this may be irrelevant but just incase)

bighornsheep

I think this is what you're looking for:
http://www.cablestogo.com/product.asp?cat%5Fid=1015&sku=03147

It's basically a connector from the power supply that controls the power going into your monitor, most power supplies will not have this, but if it does, it should look something like this:

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1621514&CatId=1078

Sie

Yeah that looks kinda right... The monitor cable has a T shape with a male and female on each side so it 'inturrepts' the power flow. without the male and female on the power supply you have to user two power cables from the mains, one to monitor and one to PC (and if anyones room looks like mine theres not many power points left even with extentions! )

Now i'll just google that for a UK seller.

Thanks for your help

[edit - once again im making great sense lol]