House swap between divorced parties -- CGT?

[MrsGrey]

I wrote before, but the situation has now changed and seems more complicated and I would be grateful for some help.
Here is the situation.

• My husband and I separated in 2004 and he moved out of the jointly-owned marital home, into rental accommodation .
• He has a flat, owned solely by him, where he has lived since 2006.
• We divorced one year ago. As part of the divorce settlement, he transferred his interest in the marital home to me, retaining a 12% interest, as I was intending to sell the home.
• We also agreed to share his CGT liability, if any, on the future sale.
• I am now in the process of selling a portion of the garden as a building plot (less that 0.5 hectare).This was always planned as part of the sale, so no argument and he will get 12%.
• The house including remaining garden is on the market. We are still on good terms, and he has suggested that I sell the house to him, and he sells his flat to me, as this fits with our space needs. So effectively we would be swapping homes.
• Though a bit bizarre, I am thinking this could be a good idea.
•
I have 2 questions re minimising the tax bill:
1. Will he have a CGT liability on the house sale, if I sell to him? Or will the liability be on the difference between the sale proceeds of house and plot, and valuation of these as used for the divorce settlement?
2. Should we go for a straight sale in either direction, or off-set the cost to me of buying the flat against the cost to him of buying the house? Thus the house would be sold for less. Would this reduce the possible CGT gain on the house?

My head is spinning. I have read the relevant portion of the 1992 Act, but can’t apply it....we will be going to a tax advisor, but would be grateful for your thoughts meanwhile.
Thanks