Freelander 2tailgate stuck

Hi guys n gals, I have a problem with my newly acquired FL2, in that the tailgate is stuck shut, even though the car system thinks it is open, and will therefore not set the alarm. At the moment (away on holiday) am having to lock the car by using the key blade in the passenger door lock - trouble is that this doesn't set the alarm nor lock the fuel filler cap
Any idea as to what I can try, please

Try to get someone to push the rear door closed while setting the alarm, or push the door in and try opening right away in a quick move, maybe battery re-set disconnect the battery for an hour leaving the bonnet open while you do, then reconnect see if that sorts it out.