Unable to default Accenta 8 system

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tamper light not coming up on first power up?

Hi - Accidently pressed panic button and accenta G3 alarm went off!.
Tried entering user code left by previous owner. It failed. Tried 0123
code it failed tried 999x code it failed.
Switched off mains supply removed control panel cover and unplugged the
battery.............Peace and Quite.

Had a cup of tea and tried 1st power on procedure.

1) Connect batt- interupted internal sounder heard.
2) Replaced control cover.(To stop tamper)
3) Went to remote keypad and noticed no "tamper" light. Still entered
0123 code. Alarm still sounding
4) Took of control cover and unplugged battery.

Checked panic button to make sure it was working properly with
multi-meter. (Not the cause of the problem)
Have checked battery and charging circuit all looks well.

What am I doing wrong?
Why is tamper light not lighting up?

Answers please.

Desperate Dan