Disaster with MK1 hinges

Last night I spent some time building a jig to enable me to drill the pins holes on the hinges. The first worked perfectly but then disaster struck... I noticed a crack on one of the hinges, which snapped under pressure!

I don't know what to do now. I could try and get another one or I could cut my losses and buy a new alloy set. I'm going to continue working on the other hinges and I'll wait to see if I can source a replacement n/s top hinge.