Change of ownership

Mr and Mrs A own two properties. Their main residence was purchased in 1992 is valued at about £280 000 and has been registered solely in the name of Mrs A since purchase. The second property is an office (bought in 2003 and owned as tenants in common 90% by Mrs A and 10% by Mr A) which is occupied by a trading company owned 60% by Mr A and 40% by Mrs A.
There are two loans totalling £87 000 in respect of the purchase and improvement of the main residence that are secured on that property. There are also two loans outstanding in respect of the purchase of the office; one of £58 000 is secured on the main residence. The other of £110 000 is secured on the office itself. All loans are in joint names and are repaid from a joint bank account...