lol, I was guessing it may have been one of the late great "arfurmo" systems traded as something eye from wickford or thereabouts.
But w/o the use of a ouija board we'll never know
swapping the colours around make no difference to the circuit,
your picture shows the strands of the cable touching.... that is probably why it was in tamper
All down to if it's wired DP or EOL. More systems are wired EOL, inverting the wires shouldn't make a difference so maybe something is loose/shorting out.
Selectable you will have to make sure they are compatible with your panel normally you cut a link within them, or you can get ones with screw terminals which you can fit your resistors in.
You can replace with any panel but the 600 has the same setting procedure as the old gardtec. It also has a built in dialler.
With the bell up here its all pyronix backlight.