UK Capital gains on US house sale

My wife and I will soon be selling our home in Austin and will be moving to Scotland.  It is our only property.  The house  might possibly be sold only after we have arrived in the UK.  Does it make a difference in terms of UK capital gains tax if it’s sold before or after we arrive in the UK?  As this is our main home would it be exempt from UK capital gains like a regular UK property?  Thanks in advance for your response.