When I moved into this 4-bed house, several years ago, I was unaware that it had previously been a 5-way student let, with the front room serving as a fifth bedroom.
It's amazing the sheer quantity of mail you get when students have been moving in and out for years, 5 at a time. My postman used to spend a good 20 seconds cramming the stuff through my letterbox in manageable chunks. Also, the number of made-up names associated with various catalogue debt you seem to get... particularly when addresses are temporary and the presence of other occupants means plausible deniability for all : /
It took me three years to make a dent in all the final demands, NHS repeat appointments, newsletters, benefits letters, etc. and I regularly had collection 'goons' at the door, sometimes clearly suspicious that I was covering for their target as I wouldn't volunteer my own details... and would instead tell them, I'm registered here ... go check the electoral roll.
(I'm identified by an anonymous 'alphanumeric code' on the register, so that's always fun)
After a few years of persistent updating of collection firms, catalogues and organisations it had all slowed to a trickle though. But only because I 'accidentally opened' the letters and updated all of the different companies and organisations myself - mainly to avoid bailiffs from breaking in while I was on holiday (A legitimate concern, given the types of visits I was getting, and that I holiday for 6 months of the year)
Opening letters addressed to prior occupants is not lawful - but it can happen, quite accidentally. No intention, no foul!
It happens surprisingly often here ... I blame my poor eyesight ; )
Unfortunately, returning mail as "Addressee unknown at this address" is apparently quite a common tactic employed by debtors, and therefore doesn't result in the de-escalation one might expect, but rather, results in groups of leery types turning up at your door and trying to menace you for access.
It was this lack of respect that really got me interested in serving legal notices,
Since I started hitting people with legal notices and 'fee schedules', my life has been so much quieter ... and my postman's bad back has significantly improved : )
Anyone currently enduring such 'letterbox hell' has my deepest sympathies.