Hi I'm a fellow Brit in the same situation. Just waiting to hear on funding from Georgetown and GSPIA.
I went to undergrad here and was lucky enough to get a full scholarship for that but back before i got it when I was looking for ways to fund my studies here there were some US banks that offered loans for international students, but I imagine interest has gone up on those too. There's the option of finding a US citizen to co sign a loan here but you may not know any I guess.
I think for me if I don't get enough funding even with the option of a co-signed US loan, I will defer for a year and at least save up for living expenses etc and reapply for more scholarship opportunities.