Alternator
 

I seem to have a problem where the battery warning light doesn't go out even after the engine has been running for a few minutes. I was double checking the wiring last night and tightening up the nuts in case the connection wasn't brilliant and I managed to snap the bolt that the blue (dash light) wire goes to :( Can the bolt be replaced or is this a new alternator job?

depends what alternator it is. Sounds like a Bosch. If its the bolt for the warning light terminal (stamped D+) They can be difficult to change as the 4mm bolt is glued and pressed into the rectifier.
Your local auto electrician can get a new rectifier for around £15 but will charge you for a full recon unit. If its nackerd anyways might be worth doing as you know it will work when you come to fit it back on

I thought this would be the case so I ended up just buying a new one off fleabay for 50 squid.