I've set up the office computer as the server because it's the one I use for ripping and downloading and is always on. I'm guessing this is unusual. If I reversed it, would I be able to do the ripping, library updating, tag changes and so on on the non-server computer and still have an accurate library?
Sorry, I wasn't criticising the way you have set it up, it was just a question to verify which machine was the server!
It really doesn't matter which way round you do it. One PC will be the server on which the physical files and library are located. But you also want to be able to access the library from MC on the client machine, in which case you need to enable library server and you will be able to access the library as though it was local, i.e. use a remote library on the client PC to play on the client PC, whichever way around you have the client and server. And you specifically also want to be able to remotely control the HTPC from the office computer (whichever is the server), in other words you want to use the local library but play on a remote machine. That requires DLNA controller and renderer.
So you have two possibilities:
Office PC: MC library server; DLNA Controller
HTPC: MC client using remote library on the Office PC; DLNA Renderer
HTPC: MC Library Server; DLNA Renderer
Office PC: MC client using remote library on the HTPC; DLNA Controller
Since the Office PC is always on, it does make sense to do it the way you've already got it, with that machine being the server.
I *think* I'm being correct in the above scenarios, can anyone offer any alternatives?
[Edit: I've just realised that DLNA might be irrelevant. The aim of doing that was to get the remote PC available as a Zone in the local PC, however I'm wondering if other instances of MC turn up as extra zones anyway. I think that's the whole point. I've never actually done it that way because I've only got one instance of MC and I'm using a DLNA media player as the second zone.]