When I took some of my birthday hats down to the post office earlier in the week, the guy needed to check the weight and size of the packages. He produced an extraordinary device that had a letterbox-size hole in the middle of it and then proceeded to try to stuff my hats through it.
The aim was obviously to simulate the actual task facing a postie, but how realistic was the experiment? I think it's time the Royal Mail added a draught excluder to their pretend letter box. Or maybe erected a full-size front door in front of the counter. You'd be able to post your own package through to the counter assistant. And if it didn't fit, you'd be forced to ring the doorbell.