My dad always used to bang on about how great his Citroën bx was because it could carry 8x4 sheets of plasterboard. Horrible car.
i agree with the other guy that said "get a trailer"
some stuff you really don't want in your car, and the number of people that will want use of a trailer for tip runs, house moves, motorbike pickups etc, you can pay for it pretty quickly by charging them 20 quid for your services