The Tax Man Cometh....
I am decidedly not an expert on these matters and I suggest you contact someone who is for definitive answers, but the key thing in my mind is the name on the deed, not the name on the mortgage. My wife is the sole legal owner as a result of the declaration of trust. The letting agents were content with this when they tried to deduct tax from us as on overseas landlord (not actually necessary since I am still employed by HM forces on exchange in Canada). The Dec of T was all they needed.
Hope that helps.
BV