"They are the only carriers to do this and I'm sure it's illegal."
Not so sure about that, because the courier problem this Christmas is being noted elsewhere. Even the 'big named' companies have had an increase of complaints and cancellations.
I have an 'agreement' with Royal Mail, which works fairly well, until recently with new post-persons who I not following the agreement that I have. This was even made more difficult by a change of sorting office for my district.
Even Parcelforce are leaving items at a local post office for collection, and the postmaster isn't a happy bunny, because of the space being taken up and the extra administration work, he and his staff are having to do. Wait till next year, when ParcelForce offer a seven day service, which they are proposing!.
Yodel now seem to use more 'part-timers' or people making 'pin-money'. Deliveries from them is based on the person delivering the item. Anything between 7.30am to 9.00pm .