OK, many thanks for the advice all. I have now connected up the
relevant pairs and isolated the mains. However, the tamper light still
comes on when I turn the key to test. I can't find a 'reset' button on
the PCB, is there something else I could try? I must also confess that
the wire to the sensor was just cut when the sensor was removed. Any
help, gratefully received.

Regards,

Bjorn.

p.s. I'm new to newsgroup posting. How do I change my displayed email,
to avoid spam?