Granturismo 13 Plate Alarm Unavailable

Hi guys
Long and short of it, have parked car on my drive and started to get "Alarm unavailable" and 2 beeps.
Taken to Maserati and they have run checks and said I have a faulty alarm sensor.
£559 fitted as it's the head unit where the interior lights are in the overhead lining section.
However I have now diagnosed that this only happens when the car is facing down on my sloped drive and not when it's facing up or on a flat surface. Alarm is fine then.
I've tried pressing the buttons in the head section that look like interior alarm and jacking off however they just flash and don't stay on etc.
I'm in 2 minds to not spend the money and just never face down park, however I didn't know if anyone had any info on this if it's still a faulty sensor or the car thinks it's being jacked up while trying to alarm so not faulty?
Any help would be appreciated.

For £559, i'd take it to a car stereo/alarm specialist and ask them to take a look first. You could find it's an easy fix with a common sensor which would likely be far less cash than the Main Stealer wants.

It sounds like a fault as Italy is nothing but hills so if they wanted to Nick one every car facing down wouldn't have an alarm on

Though I'd live with it for £559 and park the other way round