It didn't do that AFTER decorating.
The tamper shown at the time of the decorating, where were you, what were you doing that you had to stop to cancel the tamper sound at the panel?
acorn, September 2011
Repair the tamper fault.
Could be a knocked pir cover, contact, keypad or the panel itself.
After the code does it bleep 9 times?
What else shows on the keypad, could give you a clue.
Where was you decorating?