It was also convenient for the disposal of a plastic bag when there was no convenience and the flight was 4hrs30m duration
I once found that very useful in a Valiant approaching Nairobi after ten hours flying, having flight refuelled overhead El Adem. The DV panels were fairly thick and had handles that pulled them in and down. Young FED here opened it up and being a litterbug discarded all the leftover rations, drink cans etc out the window. As I finished it suddenly occurred to me that just by my shoulder were two Rolls Royce Avon jet engines that must have been having a late lunch.
Every thing seemed to be all right. Our crew chief had a crawl down the intakes but he could not find anything wrong and they got us back to the UK OK.