Ok. You should have got a tiny trickle at least. Try spinning it counter clockwise with a small flat bladed screwdriver. Probably coincidence that it’s failed. That or you’ve run it dry.
You may struggle to get to the bath waste. However, might be ok if you remove the section where the branch and basin are. Could always get a basin connection on a wc boss.
If it’s being used as a 1 way then L1 isn’t used as per mi’s. Also, have a look here: http://www.varilight.co.uk/technical-section/faqs-troubleshooting.php
If it’s the same manufacturer, the brackets may line up. As for the trv replacement, you may need to partially drain the system, all depends on which type you have.