@flyoverfred , Oh dear !
1. Based on your response ( i.e. converted main residence to income property in 2009 and being disposed of in 2021 ), you are not going to be eligible to exclude gains on main residence. Thus any gain will be taxed by the USA -- US resident are taxed on world income.
2. Assuming that you have been reporting this rental income on your yearly US tax return and also depreciating the property, your gain the property is increased by the accumulated depreciation
3. Furthermore that portion of the gain that is due to accumulated depreciation is subject to "recapture" and treated as ordinary gain -- taxed at your marginal tax rate--- the rest of the gain would be taxed at capittal gain rate.
I am assuming here that you are UK citizen and moved to the USA.
Assuming that your basis in the property ( acquisition cost plus cost of improvements by that time ) at conversion Oct 2009 was 145K GBL ( 120 K plus 25 K ) and the land portion of this 45K GBL-- thus your depreciable basis would be 100K GBL. Hence your yearly depreciation is in the range of 2.5K each year. So your adjusted basis ( for gain computation purposes ) would be --- 145K less accumulated depreciation of ( 2.5 K times 11-- roughly ) 27.5K = 117.5K GBL.
If you sell the property for 200K, then your gain would be 200K less 117.5K less 3K equal to 79.5KGBL. Of this 79.5 K, 27.5 K would be treated as ordinary income and taxed at your marginal rate -- say 20% ( ?) while rest ( 52K GBL ) would be treated as capital gain and taxed at zero or 15%.
Does this make sense ? or can I provide more info on this
There is no issue transferring the monies to the USA by bank wire or similar -- your bak will automatically raise required reports ( SAR ) and they may ask for an explanation but that is all -- it is a non-event.
If you do pay UK taxes on this sale then that foreign income tax may be eligible for foreign tax credit or deduction.
