sixwheeledbeast

Follow the manufacturers instructions and choose the best position with that as a guide. Post 2 was generic so advise would be the same upstairs.

You need to contact your installer.

It's double NAT'ed by the sounds of things. If this is the case there are a few ways to resolve. Remove NAT from one device. Correctly configure the NAT to stagger through the deivces. Or worse case option is to DMZ the first NAT device (useful to check for double NAT)

If red is radiators then SW would not be facing windows from your diagram. However, I did say that the plan doesn't help. They cover 90 degree so it can be a waste in flat.

Facing away but across any windows would be best. Both to reduce the chance of sunlight issues and cover the potential break in points better. Adjacent a radiator could be an issue whereas facing one on a wall opposite would be less so. You could also fit DT's instead if there are concerns with FA's The plan doesn't give the full picture but SW corners?

Use what the manufacturers recommend. I agree, would use Belden for RS485, that's what it's designed for.

Cost hight? Definitely biased

never installed one but it sounds like something that should be in the user guide.

Sometimes the weight issue is more to do with how balanced the drill is. If the battery is at the front it can feel twice as heavy as others.

I always thought the best location was the bin, myself.

Yep, there's a HD camera mod. With it's WiFi and small housing you will only have to worry about powering it.

RPi?

VPN's also have vulnerabilities as you say. Ports are there for hosting applications. In the future v6 will probably replace the need for NAT anyway. I do agree devices aren't open enough to know about any vulnerabilities. When they sell there kit there not interested in patching like the rest of the IT world, they move on. I think more needs to be done from the manufacturers end. Here's that blog

Contact the ICO to see what they recommend? There needs to be a secure method of transferring the footage IMO.

Risks are unsecure devices rather than the act of port forwarding. The equipment would need to adapted by having random default passwords for example. I recall a blog on this very topic by Joe a while back.

https://en.wikipedia.org/wiki/Series_and_parallel_circuits

They are free, Apple and Android.

Your looking at kit that the installers you have quotes from may have never fitted. If you are really unsure from what we have said so far, the only other things I can think of is:- Mesh, Texecom is Mesh based this maybe a good thing or it maybe a not so good thing. Generally you need more devices to increase signal security, with the idea that devices talk to each other not just to the controls. In a normal house the mesh will make little difference either should work fine. Range of devices, I know that Texecom has a large range of kit from Outdoor PIR's, DT's, Smokes, PA's .... As for others I don't know them well enough to comment on there range of kit.

The usual advice is get at least three quotes from approved companies. Choose the one you feel comfortable with and suits your needs, not necessarily the cheapest. Have you also compared warranty periods, maintenance procedures and service costs?

I would think less about the kit and more about the installer. I would go Texecom but only because that is preferred kit that I know very well. Different installers will use different kit that suits there company and they are trained and experienced on.

Internal? Series the speakers together?

printed on the cable?

I know the Pyronix Belle well and you will find is more like 500mA. PSU would be required unless you use SCB mode. You shouldn't have a system running anywhere near it's maximum output. You will need to common the negatives from the PSU's and also consider how you will get the tampers to work together.

It would depend on the application.

We are talking DIY help here. Seems sensible advise if there has been no issues. I would hope the system was installed correctly. Do I really need to have this sort of disclaimer for every DIY post? Obviously the ideal solution is have an approved installer service the system, but that wasn't the question.