When I originally contacted Sky regarding upgrading from MySky to Mysky HDi the CSR asked if I was interested in Multiroom, (same marketing technique as McDonalds "Large Fries with that Sir" etc) with the first four months free of charge. When I replied that I already had Multiroom and was upgrading both units the CSR mentioned that I was still entitled to the offer.

Sky account arrived today and yes, there was the $25.00 credit as expected.