Tvheadend

I've not used the VLC HTSP plugin specifically but in general once you've enabled timeshift you just just hit the pause button in your client and the timeshift buffer will start to get filled, unpause and the video should continue. The files are temporary so don't have a use outside of the buffer system and should disappear when you exit timeshift mode/resume live TV.

Hope I've not misunderstood and just insulted you by explaining this

I assumed that's how it should work. Pressing pause works, but then all I can do from there is press play to resume, I can't fast-forward through the video that was recorded during resume or rewind through data that was just watched.

I'm happy to use another player e.g. xine or mplayer... i just want a basic player, not a full frontend like kodi but none of them seem to support htsp.

Nevermind, I got it working! Whatever the "On Demand" option in timeshift options does breaks it. It works perfectly with this option unchecked! Hopefully this post will at least save others the time I lost trying to get it to work.

Mmm not sure what version you're using but the tooltip for that option does mention that if you enable it, that there is no timeshift until after the first request. Does seem a rather pointless option to me, because surely the point of timeshifting is to be able to rewind and pause live TV - if that option stops that functionality from working until AFTER the first event (i.e. you need to pause then resume before the buffer kicks in) then I can't imagine a use case for it.

Anyway, glad you're sorted!