Needs to be professionally monitored, as no point it calling her mobile if she's away (plus the wider area is notoriously shite for all mobile networks). I think the insurance have that stipulation as well, although its been a while since the house itself was broken in to, so that might not be a requirement any more. But it gives her piece of mind anyway.
Yes, I'd have no trouble fitting an alarm for her (though not in her house due to her utter daft thing about all wires must be completely hidden), but doesn't meet her needs. So ADT got that one a while back. And because its monitored and fully managed remotely by them, I can't add in another zone for the garage and outbuildings, they would have to do it.
She might not be so concerned about garage and outbuildings, so might get away with a separate DIY option which I'd happily buy and fit.
Currently looking at CCTV options for my eldest bro's refurbed shop, and there is a lot of interesting kit out there now, and even full IP recording solutions are quite affordable. But as little bro has found out, if the scumbags have cased the joint before, CCTV is useless if they know where the cameras are.