Part number 99761826500Source-mentioned candidate. Verify fitment and availability independently.
Cited source accounts
Tilt Sensor If you search the European parts catalog for the alarm system you will find part number 997 618 265 00 , the control unit tilt sensor. It is part of the option I536 - Alarm unit and Tilt Sensor. In the USA parts catalog the unit is still shown on the diagram but as it is not a USA option the part number for this unit is not listed. For those guys in the UK I believe you may be able to change the alarm settings
Inspect the alarm / immobilizer unit
This is a source reference. Confirm exact model applicability in the original material.