Possible SDLT assessed at full market value - the transferor being a family member.
Transfer to family member does not affect SDLT, which is charged on consideration.
additional possible CGT burden on the current owner.
It's a building company, so there wont be any CGT. However, it is not clear how a property owned by the company will be used to settle the individuals debt. The tax implications will depend on how that is achieved.
There may be other options..without exploiting the relative in a difficult situation ... eg placing a restriction RX1 to the tune of 280k, and or transferring a beneficial interest in 80% (= 280 / 350) of the property without transferring the legal title.. possibly zero SDLT for the new beneficiary and less CGT for the relative..
That doesn't give hem their money back, which is what they are trying to achieve.