Motor Control board -replace capacitor with higher voltage?
The precise value of an RFI suppression capacitor like that is not terribly critical, so using a 100nF X2 cap instead of a 150nF one should get the circuit up and running for now at least.  You can order the 150nF/275V X2 cap from most mail-order suppliers though -- I'd try Farnell, given where you're at.