You cant partset from the simple set reader. There isnt a way on that panel of doing it via gobs im afraid.
You can use an informa and the accenta has dedicated comms outputs so you can signal alarm, fire, pa etc seperatly if required.
You can connect a 16 Ohm speaker to the panel
On the galaxys they have programable outputs. If you use 2 of the outputs for your bell and strobe (normal -ve trigger) then program the outputs as BELL and STROBE as required.
not a handset as such but you could look at the nova unit. This will work on your system
http://www.securitywarehouse.co.uk/catalog/bpt-nova-flush-audio-module-black-with-black-chrome-surround-p-2457.html
smoke detector
http://www.securitywarehouse.co.uk/catalog/visonic-supervised-wireless-powercode%C3%82%E2%84%A2-smoke-detector-p-1717.html
internal siren
http://www.securitywarehouse.co.uk/catalog/visonic-mcs720-twoway-wireless-indoor-siren-p-2166.html
but check your panel version number against the compatibility list
do you have a broadband filter fitted to the dialler? ie only relevant if the line has broadband. Also is it a BT line or a NGN line.
What dialler is it?
As above. The accenta is a more powerful panel from the same manufacturer and is also a lower cost. If you require a metal end station there is a metal varient of the accenta
I would not mount a battery outside. Yes you could do this it would 'work' but is not advised. If you require more standby time i would fit an additional PSU ie
http://www.securitywarehouse.co.uk/catalog/elmdene-1381n-p-606.html
connect all your powers to this and fit an additional 7A/h in this enclosure.
id recommend a honeywell accenta. This will allow upto 8 zones with upto 2 of these as fire sensors. If you need more circuits id have a look at the galaxy flex systems or G2
http://www.securitywarehouse.co.uk/catalog/intruder-alarm-smoke-detectors-c-36_40.html?sort=4a&page=1
have a look here. Id recommend a honeywell non latching base and a combination detector
If the audio is poor that could be many factors. How is it cabled? How long is the run etc
if you have a dc based system then you can use this unit to boost call volume. But it depends on if you are using ac call buzz or not
http://www.securitywarehouse.co.uk/catalog/videx-boxed-extension-sounder-for-video-kits-and-dc-kits-p-1215.html
You cant partset on a simple set. It allows full set and unset only.
Depending on your panel you can configure the output on the simple set and connect it to a keyswitch input zone