Well, sticking a wet finger in the air, and using the same numbers, I'd say:
NPPL(M) - between 3-axis and flexwing, about 12 hours at £95/hr = £1140
NPPL(M)-NPPL(SEP), about 15 hours at £125/hr=£1875 + £95 skills test = £1970
NPPL(SEP)-JAR-FCL PPL(SEP), about the same again.
So, if you want to go for a complete set, in the order NPPL(M), flexwings --> NPPL(M) 3-axis, NPPL(SEP), JAR-FCL PPL(SEP), you'd be looking at a total bill of about £8k, (plus, which I forgot to put in before, licence issue costs to the CAA). Not a bad way of going about it!
G