In England (don’t know about Scotland) house numbers are assigned by councils, acting as Street Naming and Numbering Authorities.

@cr2

The people at the SG12 delivery office (Marsh Lane, Ware, SG12 9WR) must know the answers to your questions: it is they who are responsible for emptying the postboxes each day.

Hampshire's Mobile Library service(http://www3.hants.gov.uk/library/mobile-libraries.htm) has about 1200 stops, each of which is visited for 20 or 30 minutes once a fortnight.