James: Learning how many twinstars there are at each training location is pointless. Learn roughly what the course entails and where you complete each stage.
Just practice the maths and it will come back over time.
Remember the person interviewing you will most likely not be a pilot. If they ask why you haven't done more I'd say something along the lines of
"I took the hours trial to ensure I did enjoy flying and wanted to pursue it as a career, since I knew I wanted to train with CTC (
) on an integrated course I considered it a poor value of money to obtain any more experience when I would complete it with CTC" You get the idea... I had very little flying experience when I started but was never asked the question.