UK CGT on selling antique when retire abroad

[ABUkMan]

Hi All, My wife and I am about to retire abroad beginning of April, flying out on 6th April 2021. We have been living in the UK for the past 30 years, we are British Citizens. I have a few pieces of artwork and antiques which I have collected over the years. Each piece is valued above 10k. If I sell all the pieces abroad in say Dec 2021 (within the same tax year I leave), would I be liable for UK CGT? The country I am retiring in do not have CGT. I do not intent to return to the UK in 2021 or for at least a few years. If my wife and myself do return, we will be staying for less than 3-4 weeks in a complete tax year. We do have a small house worth around 200k in the UK which we probably intent to sell at some point during the retirement. We have no children. An edge scenario is that if my wife may need to stay in the UK 2-3 months longer before joining me, is there a distinction in terms of CGT between me selling the antiques or her selling it when she does join me say in June 2021. Any help would be greatly appreciated!