2007 Freelander 2 HSE

Just recently when I prerss the lock button on the keyfob the car locks, and one of two things happens:

1 Almost immediately, the alarm sounds briefly a few times

2 After around 30 seconds the alarm activates.

Did a bit of digging and found that if I use the key in the passenger side to lock the car, the alarm does not sound.

I can't find the original info, but do recall that it indicated either the volumetric or perimiter sensor was not enabled when using the key.

Looking some guidance please.