I'll check whether I already have an M10 tap in my kit, because if I don't I definitely have M10 nuts and epoxy
If when I show them to the homebrewing world they decide they want me to make some more I'll make sure I have the right tap. Cheers all for your help!
Good point @forteh, I'm having a properly duncey time with this!
What's your thoughts on printing the threads and then chasing them with a tap @monkeyseemonkeydo? With nothing but hand tools I feel like I'd be susceptible to drilling the holes off centre or not straight and ruining the piece. Is the idea of printing the plain hole and tapping it a better one?