Certainly don't by a HiFi brand name and dont bother with Banna plugs either...especially if its a temp setup....
12 or 14 AWG (or similar), oxygen free, copper speaker cable can be got from the interenet (Ebay for Example) for about 10 quid per 10M or there abouts. So you can get what you want for about 15-20 quid.
They probably have something similar at Maplins.....but seriously....why bother with banna plugs???....They make ****** all difference. People go on and on about gold plated connecters, better conectivity etc. But if the speaker cable you are using is copper...and the wiring in your speakers is budget/mid range.....there will be no audiable difference. I challange anyone it listen to the same system - one using banna plugs / the other without and actually be able to hear the difference. The only reason for using banna plugs is ease of installation.... So if your setup is a temp setup why bother...your only going to be using them once right???