I have still got around 70 hours to fly before I have my 100 P1 and I have almost completed my exams, and I reckon there is another £32,900 to find!
Don't forget to include all the other stuff peple have suggested (food, travel) but also factor is 15% for additional hours and a test resit or two. Don't want to be depress you, but if you fail the IR, the re-test and practice can cost a few thousand. Bit of a bummer if you're almost there and you run out of money.
Best of luck