Home DIY

Cheers for the info. I won't be doing it myself so I don't need to know too much about the install.
I'm pretty sure it's meant to be done with local authority permission or some crap anyway and for stuff like this I'd rather have a pro do it. Just knowing what options are available is nice though.

It is illegal to work on unvented systems unless suitably qualified so no choice in the matter(although you could in theory do the install and have it commissioned by an 'expert').

This of course means I did not repair one of these systems recently. In fact I was nowhere near the place on the day in question...