Hi Speedy
I would have to say that affiliate links are managed acceptably by
Webhosting UK (just as James has answered) and unless you personally know that someone has registered through an affiliate link provided by yourself, it would be prudent not to suggest that WHUK have done anything wrong
The link you have for your affiliate is not really standing out as such, but as a suggestion, try posting the link on anywhere you visit too, and that may help boost the hits (and potential sales) that you may have
I myself have not received any commissions (in case you wonder) but my one link (yes I know I'm sad by not posting it everywhere guys

) has received 45 hits, so that means it works
Keep up the site though and as I say, try posting the link across more sites, or pages, and see if that helps improve your chances. A person who owned a really large and profitable double glazing company once told me - a thousand leaflets will produce 2, perhaps 3 results
Go figure that

Best regards
MrTWS