How to report UK home sale

It was my primary residence for 14 years so I don't think cgt applies does it?

this view might be in line with the law, but is directly opposite to the official IRS instructions. Please refer to page 7 here: https://www.irs.gov/pub/irs-pdf/i8938.pdf

Reading further, it's my understanding that if you don't know you're going to be a beneficiary of an estate from time of death until distribution. (your Great Uncle Bulgaria that you've never meet unbeknown to you; has you in his Will) then you don't add to the 8938, as you have no idea anyhow. If you know your Great Uncle Bulgaria has you as a beneficiary, you'd check the $0 - $50k box, as you have absolutely no idea what the ultimate distribution will be until received.(estate needs to pay debts, funeral fees, lawyers and so on).
Once you have received the distribution, then this would go onto the 8938 if you meet the threshold. Then you'd need to file a 3520 if the amount is over $100k. So if the inheritance is under $100k, the IRS has another way to know of this via form 8938.

I can gather that if the estate takes a long time to get distributed and you are initially aware of the your interest at death, you maybe filing a $0 - 50k position for several tax years.

The quandary being if you don't meet the threshold to file a 8938, do you anyhow (knowing that you may receive an inheritance above the total threshold.

An interest in a foreign estate would be a specified foreign financial asset only if it is “held for investment.”  Treas. Reg. §1.6038D-3(b)(1).  As Guya mentioned, the instructions to Form 8938 are a little misleading because they do seem to suggest that ANY interest in a foreign entity is required to be included on Form 8938.  Fortunately, the instructions to the form are not the law.  Therefore, it generally would not be necessary to include an interest in a foreign estate on Form 8938.