Thanks guys, this is all really helpful.
This may sound vague, but how much is a 'good' amount to purchase?
Also do you know if the cord at http://search.stores.ebay.co.uk/The-Trojan-Group-UK_cord_W0QQfciZQ2d1QQfclZ4QQfsnZTheQ20TrojanQ20GroupQ20UKQQfsooZ1QQfsopZ1QQsaselZ286126692QQsofpZ0 is...