Let's assume all your predictions are accurate:
p1 -100
p2 - 88
p3 - 100 (pred)
p4 - 100
p5 - 60-65 (pred)
p6 - 95 (pred)
m1 - 98
m2 - 55-65 (pred)
m3 - 90 (pred)
s1 - 87
s2 - 95+ (pred)
d1 - 100
Maths must consist of P1-3 plus three of P4, M1, M2, M3, S1, S2 and D1, subject to the following restrictions.
(1) You can't include M2 unless you have M1, M3 unless you have M2, and S2 unless you have S1.
(2) You can't include all three of M1, S1 and D1.
(3) You can't include all three mechanics modules, because that would leave two level 1 modules for Further Maths, which isn't allowed.
So I guess that means you will get P1-3, M1, M2 and S1 for Maths. Total UMS: 533.
This allocation leaves P4-6, M3, S2 and D1 for Further Maths. Total UMS: 542.