How hard is it to fit one? Looking at the moment and can get TEXECOM RICOCHET PREMIER ELITE 48 for £272.
It sounds like the control box is all hard wired for power, and then the wireless extender makes it "wireless"?
Powering up and learning PIRs, door contacts etc isn't tricky, the trickiest part is setting up the zones on the system (like how a PIR is set up, what conditions will cause an alarm signal, a tamper signal etc). Alarm systems aren't always that clear, certainly not until you get a little familiar with the menu, but like many things, you can figure it out if you're looking for a basic set up. I quite like the Texecom menus but that may just be because that was the first panel I started tinkering about with.