if you can afford it, its free delivery
http://www.charterhouse-aquatics.co....dia-p-189.html
budget version of the Eheim i just listed, although the Aqua One does claim on the stats to have a more powerful pump (flow)
http://cgi.ebay.co.uk/Aqua-one-canis...QQcmdZViewItem
Or..... you could go for x2 Powerful internals like x2 Fluval 4+ that would set you back a total of about £50 including postage on ebay i think, trouble with them is more maintenace, i think they will do as good a job, just more maintenance.
Also depends what fish you keeping in there Pete?