It redirects to an area on their site that has no link to renewals at all.
I took over from my wife’s attempts when she said it was all too hard! and went to http://www.subscriptions.co.uk and found my way from there. The result is “she” has kindly renewed my birthday present for another year.
Funny. I had a similar letter and had no problem with the link. In fact, I just clicked on the link in your posting and went to the renewal section, straight away! I very kindly bought myself another year’s subscription for Christmas.