Most tax efficient way to dispose an asset (BTL property)?

tebthereb

Your tax residence may alter, in the UK or other jurisdictions, if your circumstances have changed such that you are outside the UK more.

There may also be planning to be done with pension contributions or other investments.

As you have a property portfolio there might be some longer term planning you could benefit from. Possibly too late to spare you tax on this sale, possibly not.

With a gain of 100k and assuming from what you have said that you and your wife have a reasonably high asset base and income, I would have a chat with an accountant at least. Most offer a free initial meeting.