You can use either the HKC with standalone contacts in enclosures eith HD external contacts
or the pyronix enforcer.
Both will function without internet but notifications wont be possible,
Note our products are designed for professional installer use
It sounds like you have either a failed controller or pir.
DIsconnect all pirs andding one of them (test each one) and see if the fault disappears. If so start adding pirs back into the system until the fault reappears
Honeywell Galaxy ASK Keyprox Proximity FOB [YXO-0020] - £5.39 : | Best Price Promise | Security Warehouse Professional products
honeywell fob. there are also honeywell compatible available
Id look at the fike twinflex or better the addressable fike as this provides automatic hush in a HMO type environment
Fike CIE-A-400 2 Loop Addressable Fire Alarm Control Panel [540-0001] - £631.41 : | Best Price Promise | Security Warehouse Professional products
I dont know of a manufacturer that supplies boards only. But may be available as a special order. Usually one would replace the whole sounder to keep it looking as new as spossible as this is the detterent
Re the cctv do you have a preffered brand? Agree on the toy town stuff most budget equipment is exactly that.
Alarm system wise again i dont know your expereience or preffered equipment?
examples
Secware Double Flashing Battery Powered LED [SECWARE-DBFlash-LED] - £6.72 : | Best Price Promise | Security Warehouse Professional products
HKC Decoy Flashing LED Unit [UKBPStrobe] - £18.70 : | Best Price Promise | Security Warehouse Professional products
Bentley Double flash (unit with two LEDs) [AT-361] - £18.59 : | Best Price Promise | Security Warehouse Professional products
They will last a couple of years. I have the Bentley one on a garage at home and it lasted 5 years so far.
No not a mains powered one. There are battery led kits available but the only way to emulate a sounder is to use a real sounder and power it from a powersupply