Certainly the problem when I worked as crew was that we didn't have a buggy policy with regards to delivery of the buggy after landing. This probably isn't what you want to hear but, in my experience, it often depended on the ground staff's mood, flexibility and timescales as to whether buggys would be delivered to the door or not.
Also it may not be the case now but at LGW (and other BAA airports I would imagine) buggys were not allowed to be taken on the passenger buses so if we parked on a remote stand that required passengers to be shuttled to the terminal they couldn't take their buggys with them as the bus drivers wouldn't allow it.
So, unfortunately, in an ideal world it would be nice to give an answer in black and white (ie "You will / won't receive your buggy after landing) upon booking so that you could pack your handbaggage accordingly but as you can see it's not always that clear cut.