Erm...well here's a Bore tool..and the trials one fits the Moto V2 calliper too. Sooo I assume they;re the same Pistons? Couldn't see any hope trial pistons when i searched.
How badly are they scratched? Maybe polish them out?
Just a bore tool...which you can make, or just use an isis BB axle if you're pikey
Isa is unnecessary if you're not a tool and don't get dot fluid everywhere.