@persco Clearly Ofcom, after lengthy consultations decided to apply the rules across the board.
A shortcode such as *pac* would be memorable, if it is possible to implement. However the shortcode will be identical on all Networks so after a while it would be very common.
The new rules also affect number changes which currently are limited to online requests with giffgaff. A different shortcode will be needed for that procedure.
Networks (will) have had 18 clear months to update their systems.
Standardisation the system, industry wide will be good for the customers of all networks and with other changes, cheaper too.