Is this not just a UK thing.....
I don't think so....it's just that the UK has tried to clarify some slightly ambiguous wording in PANS-ATM.
Para 11.4.2.6.2.5 which says 'Level restrictions issued by ATC in air-ground communications shall be repeated in conjunction with subsequent level clearances in order to remain in effect' is the main point of contention.
PS - I have no doubt that plenty of people will say that a new route is not a level clearance or that it's all perfectly clear in PANS-ATM. But I'm afraid I'm the sort of person who prefers things to be clear and simple whenever possible.....rather than guessing what someone else really meant. When I was controlling the real benefit was that there was far less form-filling to be done!