I wouldn't rule out Texe just because you feel your house is 'too small' - its still a great system, and
well manufactured. With 9 devices or so. the mesh should have plenty to work with! Plus, the Texe 12W has
4 on board wired zones which might be useful. The HKC and Siemens are good too, although you might
have to look around a bit to find a Siemens installer!
I always bring demo kit to customers myself, I know some think its a bit old-school but from a customer
point of view that's exactly what I'd want - to see what I'm getting not just a scruffy piece of paper with
a single figure on it.
And as everyone said, don't just go with the cheapest - use the company that you feel the most
happy with, and do invite some SSAIB companies to quote for comparison.
Also be aware some advice is for your benefit, not just to make more money for the company!
For example, the number of times I've been told "we want to save a bit of money, so don't think
we need those detectors upstairs" is a good example. It's only when I explain without them, a burglar
could, for example, be straight through the door, up the stairs, and not have to worry about an alarm,
let alone a confirmed alarm, for a good 20 seconds it hits home.
Good luck!