In case this has passed anyone by. If you have a less-used postbox by RM's criteria, your postman/woman will be emptying the box on their round (starting from September, exact dates may vary, not sure), so that will be your 'last collection time' for that day. 'I'll get it in today's post' will therefore now mean 'I'll get it in today's post if I can guess what time the post is coming today and get to the box first' - ie anytime from 9am Mon-Fri and 7am on Sat. Affected boxes will be marked 4 weeks ahead of the change, ie should be already.
http://www.royalmail.com/personal/he...postboxes-faqs
"Research shows that postal users are positive about the idea of moving collections, particularly from low-use boxes, to link with delivery. 91% of users did not choose their box based on collection time." Most likely because they just assume there will be a collection from that box around the 5pm/6pm mark, so any box will do.
Incidentally if my local box receives less than 50 items a day, then I'm a monkey's uncle.
Once again, cheers, Royal Mail.