Who do I get in touch with to discuss these things? My partner has a 2011 (I think) MX4 hardtail which hardly ever gets used, but I lent it to a (roadie) friend the other day so he could see what mountain biking is all about and the mech hanger snapped (So he now, correctly, thinks that mountain biking is about bikes breaking).

Tried emailing them but I’ve not heard back and can’t find anything online…

BETD have a chart where you can look stuff up;

http://www.mountainbikecomponents.co.uk/result.asp?CategoryID=193

Ridgeback aren;t listed but you can look for the right shape.

Evans Cycles used to list a wide range of replacement hangers, I don’t know if that’s the case?

Ridgeback are a Madison brand, so any LBS should be able to order one in for you.