If you cannot find the answer to your question on the Mensa website, please use the form below, or contact us by post, telephone or fax.Registered Office address. British Mensa Ltd. St John's House St John's Square Wolverhampton WV2 4AH United Kingdom Tel: + 44 (0) 1902 772 771 Fax: + 44 (0) 1902 392 500.f you cannot find the answer to your question on the Mensa website, please use the form below, or contact us by post, telephone or fax. Registered Office address.