One of the things I noticed with a flight and car hire package occurred when my flight home was cancelled. That meant I needed to extend the car hire by a day. BAH said they couldn't do that and I'd need to arrange it directly with the car hire company and claim back any charge. I was only in Glasgow and using Avis, with whom I thought they were partners.
Seemed a bit odd but then I don't do many travel agent package holidays so maybe that's normal.