shipping may require someone to receive your luggage or the shipping company has secure pickup storage that you to pick up upon return. i would prefer shipping, if the logistics is not a problem for the same reason S80 stated. also consider using a parcel box instead of a luggage. less conspicuous and will be lighter in weight. otherwise, 6-7 hours should be sufficient time and storage is a viable option. not sure about bounce, but there is one service at the heathrow airport and it seemed to be accessible 24/7