I have recently bought a 56 registered Astravan which is factory fitted with an alarm. It seems impossible to even lock the car if the tailgate is open with dogs in (or even with front windows open a few inches) without the alarm going off. The van can be locked with the key but ONLY driver's door: the passenger door & tail gate are not locked if the key is used. How stupid is that not to have key-activated central locking. Any suggestions please as to how to lock the thing without activating the alarm? Thanks.

I have an alarm on mine and end up leaving it unlocked if the dogs are in the back or like yourself have to risk the alarm going off.  No advice but I know how you feel.

I have a crate in the back of my car for the dogs and attend agility shows so the tailgate is often open. My alarm doesn't go off but the courtesy light stays on and runs the battery down.  A friend showed me how to get round this - I have to push in the locking bar on the tailgate lock to fool the car into thinking the tailgate is locked shut and I can then use the fob to lock the car with the tailgate up. When I unlock the rest of the car I have to manually push the handle in on the tailgate and as one would to open the gate if it was closed but the car was unlocked.

I have wind down windows in the back of the car and it is these I leave wound down a little rather than the front electric windows. Some cars have a switch that overides the lights in the cargo area but mine doesn't have one so have to resort to the above method which does work well. Might be worth seeing if yours would do the same.

Check with the dealership or double check in your manual.  We have 2 Chrysler vehicles and both of ours have a setting where if you click 'lock' a set number of times it activates the outer alarm, but turns off the internal sensors.

@Harley re the lights -  there should be a dial in your car where you can actually turn off your internal lights so you can leave the doors open without running down your battery

We have a switch/button in the car that lock all the doors when you are in the car without switching on the alarm. We then lock the final door (which is the passenger door as car is French) with the key.

Some interesting ideas. Thanks.
To over-come the light problem I used to remove the rear bulb. It was too small to be useful anyway. This vehicle, the light goes out after 5 mins if tail gate is open. Useful.
If only women designed dogmobiles!

@Harley re the lights -  there should be a dial in your car where you can actually turn off your internal lights so you can leave the doors open without running down your battery

Thank you - it wasn't just the lights though, I need to be able to lock my car but leave the tailgate open so that I can leave my dog in his crate whilst I walk the course, visit the loo etc :-) Using the method I described means I can now do all those things when I am at a show by myself :-)