How to Cancel HST in Canada from UK

Hello. I'm hoping someone here can help me with this problem. I am in Scotland on an Ancestry Visa and will be getting married in April 2012. I am still receiving HST cheques in Canada though and want them to stop. We don't plan on returning to Canada no for at least 4 or 5 years and I don't feel like I should be entitled to them anymore.
Has anyone else ever done this with Canada Revenue???