^
I feel your pain having come in the other direction.
International tax law seems like one big con.
Trying to read up on , and get definitive information, so as to allow for some sensible planning and modeling outcomes of actions seems like a non starter.
All the rules seem discretionary, so you have no way knowing how they will be applied to you, until they are!
Any information that is out there is couched in caveats, and advice to "refer to a professional", although finding someone with relevant expertise in the required area is problematic.
A case in point. Some other ex pats we knew were returning back to the UK, having rented out their house while they were in the USA.
If they sold their house in the UK, in a tax year when they were non resident in the UK, then they would be exempt from capital gains on the sale of the house in the UK.
If they sold the house after their return, they might be liable to capital gains made while non resident.
So essentially they were forced to sell their house before returning home in order to definitely avoid some possible liability.
They then bought a new home in a new location in the UK as the husband was relocating with his company. Only to be made redundant shortly after his return to the UK.
The uncertainty and time horizons involved make this a less fun subject.
Selling and Buying a house as an ex-pat involves timing three markets (Selling house market, foreign exchange rate market, buying house market), so whatever you do will be non optimal.
Don't get me started on rates/charges for foreign currency transactions.
At least now there are come currency brokers who can set you up with some ForEx Options to give you a hedge against currency fluctuations. (e.g an option to purchase currency at a fixed rate, in advance, for a price )