You may consider going off to sunny Florida.
Good schools there include EFT, Naples and OFT.
Like you, I also have about 20 hours, which I gained from an RAF Flying Scholarship in 2000.
I am going out to EFT, Florida in April to do about 20 hours dual and 10 hours solo over a period of 14 days.
I have already done 4 ground exams over the last 5 weeks and will do the remaining when I get there. This is highly advisable!!!
Before you leave for USA for training, you will need an M1 visa, pay SEVIS fees and register with TSA. All this involves time and money.
Dont worry, your school will provide you with detailed instructions on the whole process. At least EFT did anyway!!!
I would also give at least 10 days to complete your remaining 25 hours or so.
Good Luck!