as an employee of Royal Mail . . .
I see the situation from both sides, as a postman and also a customer. While I agree wholeheartedly that there are many things that my employer should do to better service the needs of the customer, small and large alike, providing an infrastructure that aims to deliver to every UK address 6 days a week does not come cheap and whereas Royal Mail's contract obliges them to do this, the same rules do not apply to their competitors. It also occurs to me that the competitors, given the opportunity, would not have their own post boxes as they require emptying at least once every day, there are few companies who would be willing or able to carry out such a task.
In general when Royal Mail delivery staff go out they are expected to at least attempt to deliver any packet / parcel that is approximately shoe box size or smaller along with all the other letters, bills and unwanted leaflets that you routinely get to 500-800 addresses. Where I worked you weren't allowed to leave the office to start your delivery round before 07:30, this meant that the vast majority of the customers would have already left for work, and even if you knew that they would not be there you still had to take the item with you 'just in case'.
Times have changed and provision needs to be made that will accommodate the more typical scenario where there is no one at home during the day to accept signed for items or those that are too large for the letterbox. One suggestion I heard was to double the number of delivery staff and halve the hours so that more could be delivered earlier and catch more people before they left for work, I wonder where all these delivery staff will come from that are willing to get up at 4am for 4 hours work .
Fortunately for everyone there is a solution however, buy things in shops, that way you avoid all the things that are poor about delivery services, the downside is that you then have the problem of surly and poorly trained shop staff instead of a surly and poorly trained postie
:p