Start with this
"Given a few hundred quid, it's probably better spent on good locks and door/window frames first, before splashing out on connected cameras."
Now that is good advice. I'm a nerd of the first order and love a good technical toy errr solution but for home security, make your home difficult to get into in the first place. Then ensure that valuable stuff is hard to remove.
Telly? Most wall mountings have holes all over the place so put a bolt through them with a castle nut or something to make it hard to remove without a toolkit. Other things with a case - put a bolt or two with a really wide washer (it's probably a plastic shell so spread the load) through it to the unit that it is in or on.
Where possible, put IT related gear in the attic. Things like NASs and camera watchers can be homed up there nicely and you then have a relatively easy drop via the external walls and conduit (generally wife friendly when confronting her aesthetics mode). Get a UPS (forty odd quid off of say APC) and connect it to a nearby lighting circuit (nearly always available in the attic) if a ring isn't handy and you don't fancy putting in a dedicated circuit off your consumer unit. Do follow wiring regs though - be safe or get someone in ...