If you only get paid £15-20 per hour (flying).
2-4 hours a day, if you are lucky. £30-£80 (lessons between 30 min and 1.20 for rare nav ex's)
minus fuel to get there £8-10
2 days a week £240-£320 minus fuel and medicals / renewal of ratings etc...
You won't get paid for briefings as it is part of the lesson, but long briefs, i.e. the first nav ex is about a 2hr brief, you should get £20 for.
If the wx goes out of limits, which is usual, the lesson is binned after 20mins. This is common in the circuit if there is a Xwind and the student is trying to land. If he/she is almost solo and it is a bit gusty, why fly and burn his money.
Oct-Mar has some bad wx and good. Look at today. Mist and poor vis. Can't teach nav/stalls/effects of controls/ turning/ climbing/descending all needs a horizon or they will only get mad you made do with the conditions. The result is a student who spends 6 months in the ct because they can't fly straight and level. You may have got £20, but they have been stitched up....