You won't really know until you try Craig, unless you can find someone with the same wheel and brake combination, which is probably unlikely. Best bet is probably to buy (or borrow) some 5mm slip on 'shim' type spacers and test fit the wheel - if you need 2 shims to clear the caliper then you know that you'll need 10mm hubcentrics, 3 will mean a 15mm spacer and so on. The problem is that 9j et25 up front is already going to be pretty much flush, so having to add spacers to clear the calipers is going to make the faces poke out from the arches, so to make them fit you may need to either run a stretch on the tyres, or go back to jspec calipers.