Help needed wiring vortex bell to pyronix octagon panel

I've just bought the same bell box. You've probably worked this out already, but for other people reading the thread, the connections you have are correct:

BA TG- (Bell trigger signal from control panel to bell box)

S+ Hold + (+Supply from control panel, also 'holds off' the alarm)

-B Hold - (-Supply from control panel)

BT Return (Tamper return to control panel, from the tamper switches in the bell box)

STB STB- (Strobe trigger signal from control panel to bell box)

S+ might also be marked +B

If the LEDs are flashing together then the alarm has been triggered. If they are flashing alternately then the alarm is working normally. They will flash once, twice or three times in 5 seconds:

Once - The hold+/- connections are not getting the 12-15v they require

Twice - The internal tamper switches on the bell box are causing the alarm

Three times - The tg- input is no longer grounded, and so the alarm is triggered.

I assume they are flashing three times, in which case ground the tg- (BA) line at the control panel (connect it to the negative supply line Lurch) and see if the alarm stops and the LEDs flash alternately. If this doesn't work then the tg- line probably isn't wired correctly in the bell box.