Regarding junk mail from Royal Mail.
RM are legally obliged to deliver mail as addressed and paid for by the customer.
The Mail Preference Service can reduce the amount of junk mail you receive.... eventually (expect to wait three months before seeing any appreciable difference).
But and this is a big but, RM are cynically and deliberately circumventing the MPS.
Every postal address in the UK is, by default, opted in to the 'Door to Door' service which enables you to be targeted for unaddressed marketing mail (flyers, leaflets and those big red Virgin Media envelopes etc). MPS can only prevent addressed marketing mail.
See what they did there? Clever huh?
Now, to opt out of receiving this junk, you have to request a form from RM, which you then have to complete and sign.
RM will not stop sending you unaddressed junk without your signed 'permission' to do so.
You can not opt out by telephone.
You can not opt out by email.
You have unknowingly been opted in to a 'service' without you permission (signed or otherwise).
RM use the 'legally bound to deliver mail as addressed' excuse to deliver unaddressed fishing marketing.
RM are not legally bound to accept or solicit contracts for these mass unaddressed mailings.
BTW, if you do fill out the forms and give RM 'permission' not to send you junk, it expires after two years.