Yes, so difficult to figure out the relay types there.... RL1 is a double pole double throw Siemens relay, do not know the coil voltage but likely a 24VDC version, as those are cheap and common, and 35V rating for C2 says it is likely that. Also is rated for 2kV withstand between contacts and coil.. Easy enough to measure, look at voltage rating of . RL2 is a mercury wetted high voltage reed relay, as that is the spec in the standard for the relay, so you get a fast rise pulse out of the 470pF 1500V capacitor to simulate the human touch model. 330R resistor is the emulated body resistance.
Charges the 47n capacitor to a high voltage, then uses RL1 to discharge it when power is off, via the 2 series 10M high voltage resistors, as well as to connect it to charge the 470p capacitor via the one 10M resistor. The reed relay then pulses to simulate a touch. Would be nice to see the bottom of the board to reverse engineer the circuit.
Detector is easy, the CA5260 is a CMOS input opamp, so it is arranged there as a simple flash converter, using a ladder of resistors to sample the pulse input, and the 74HC279 latches hold the maximum voltage from the converter to display.
http://www.intersil.com/content/dam/Intersil/documents/ca52/ca5260-a.pdf