I'm going to ask a power raise. I'm moving from 3kW + 30% (15A) to 4,5kW + 30% (25A).
I'd know if my main feed (3m, 2,5mm2) is enough to hold the new max rate.
EDIT: I've checked my main feed and it's actually 4 mm^2, not 2,5.
2.5 mm2 is equivalent to #14 for us Americans, which is required for use on 15 A circuits (or a larger wire). On a 20 A circuit, you need (at least) #12 [4 mm2], and for a 30 A circuit (the next step up for your 25 A needs), you need #10 [6 mm2].
So, given your current wire size of #14 [2.5 mm2], you cannot increase the capacity of the circuit at all.