Hi Susan, thanks for your detailed help.
The taxes are filed manually (since no tax is paid, none was taken, so there's no hurry to get a refund.) I will consult with my mother's tax advisers in the UK to determine if there is a way to proceed per your recommendations, filing the UK taxes first and getting an extension on the US side. There is only a 10 day window between when the UK taxes open up on April 5 and the US tax season closes on April 15.
I am definitely against paying the tax and then claiming a refund through amendment. They didn't take any tax out, so sending money only to claim it back just doesn't seem like the right way to proceed. Also, the last time we filed an amendment it took over 2 years for the refund to come through, and with the state of the IRS today I don't expect that will have improved.
Thanks again for your assistance.
