I'm currently self-building a house and am trying to decide on the alarm system (wired v wireless primarily)

We have a pet (uses ground floor only) so PIR may be an issue. There are 3 doors (entrance, back and bi-fold) and 9 ground floor windows, plus 2 upstairs by a flat roof. I think I'd prefer wireless if possible, but I have a detached garage with games room above (1.5m from house). I also like the Texecom flush control panel - can you connect 2 of these?

Can you recommend a system please?

Initial points

If you can cable you should. I would run cables to all detectors and more

Any movement detector is best only detecting movement. Expecting a £30 device to tell the difference reliably between a pet and a person etc is asking for trouble. Yes they are sold as a feature but i would never recommend any of them for reliable catch performance and false alarm reliability

You have to match keypads to control panels. I wouldnt recommend the texecom over say an spc or a dimension 

On the bigger panels you can connect upto 32 keypads depending on the panel specified

Your installer will advise best on the equipment to use