There are so many features royal mail could add to letter/parcel delivery that users might want to pay for, and would cost them nothing. Eg.
* See what mail is headed your way. They could have email/text/app notifications of mail that's headed towards you, including a picture of the outside of the parcel and estimated delivery dates/times.
* The ability for the receiver to pay to prioritize incoming mail. Sometimes you're sent something with slow second class mail, but then realise you really need it urgently, so could pay to 'upgrade' to express service.
* Auto upgrade all mail headed to you if you buy stuff online and hate businesses that send stuff with cheap shipping.
* Perhaps an x-ray service so you can see inside parcels - would be handy for businesses that do returns who need to check the real goods are headed their way.
* Super express services. Pay £500 and we'll dispatch an employee direct to your address with the parcel, and it'll take the driving time plus 10 minutes. Operationally it's only the same as the employee going home sick midday.
* One off redirect services. 'I'm at work today, send my parcel there'.
* Allow adding delay. 'Im on holiday, don't deliver any mail for me this week, I don't want someone breaking into my house to steal it'.
* Allow binning a letter before it even arrives - for spam and junkmail. Maybe have automated spam filters which can be enabled (and binned items can be held for a while before being actually destroyed in case of classification error).
* Allow understanding names of people at your address - eg. "Return to sender any mail addressed to Fred Smith, he no longer lives at my house"
* Notifications that the postman is 5 minutes away and has something too large for a regular letterbox. That means the postman won't have to wait so long after ringing the doorbell.
* "Letter to email" service. If you ask, they open the envelope and scan and email you a pdf of the contents. Then you get the info faster, and is also helpful for people away from home, businesses that need a mailing address but have no employees to deal with mail, etc.
All of these services would be free/cheap to implement, and each could be a chargable service that earns the company money.