sixwheeledbeast

I have explained the best way forward. Replacing your bell would be a waste of time and energy even if you can find a like for like replacement.

That type of bell hasn't been manufactured in many decades. Replace for an SAB of your choosing you may find a model with the aesthetics your looking for. If you need help with the wiring upload a picture of the panel end terminals and we can try and point you in the right direction. https://www.securitywarehouse.co.uk/catalog/intruder-alarm-c-36/sounders-c-36_45/

Like most "wave" devices. It sends a frequency into the room and monitors for changes to the signal reflection.

Forget all that keyfob and Google Home rubbish, have yourself some quotes for a decent wired alarm fitted properly. You could potentially wire it yourself to keep cost down if you approve this with the installer first. Consider the deterrent factor of a external sounder with an approved company on. As for CCTV I personally avoid both Dahua and Hik, very often CCTV is not fit for purpose on many domestics, better to spend more on the intruder and physical security first IMO.

Wouldn't provide me with much confidence. NVM could be on the way out. I am all for maintaining a fully working system but if your getting problems at that age it's time to consider controls replacement.

Seems odd to have an error on Z12 if you have no expander cards on the system (4 zones)

You can fit G3 gear but you can't make it conform to G3.

If it doesn't charge the battery I would consider the panel as not operational, it's one of the main functions that would be checked on a annual service. The panel has done it's job, proping it up with another supply will only create more issues down the line. Have the controls replaced and a full system check while your at it. SLA standby batteries last around 4 years and the external sounder battery may likely be shot if not replaced since installation.

Cisco HP Netgear Draytek... I'd expect to be looking around 230 for a Netgear without fibre ports more for the others. If it doesn't need any features then Netgear would do, most are managed at that size.

It's all relative. I went out to someone last week with a 2 year old Yale thing fitted by a spark that now will not support it for her. I explained the pros and cons, it's booked in for fitting a wired system after Christmas.

Most Pyronix boxes of all eras have the need some tweaking with the box tamper spring/leaf somehow.

If it sounded outside the lid opened.

If it's a "Texecom" box one solid light indicates a fault. It may not be a Texecom one, however possibly a good idea to have your system checked over if it hasn't been done.

Not very helpful posting a picture of something that's not yours when asking for help... Good luck with your Agility certainly not something I would fit, if the above system was yours i probably keep it instead.

Yes to fully decommission a system you will have to get up to the external sounder. Looks like like the panel and possibly bell has been recently swapped, going from the colour of the plastic, the iconic keys, the hold-off working and the paint over where the original panel was. Does the current system work? What would you replace it with?