I wonder if the more established (and generally higher ranking in league tables) unis rest on their laurels rather with accommodation?
I would imagine the universities have a rolling programme of accommodation upgrades. Possibly your DS has just been very unlucky @icanbewhatiwant and has one that will be revamped next year (possibly when the new accommodation block has been completed)?
You'd kind of hope that the rooms and flats would be thoroughly cleaned and then locked up over the summer break, so the only mess to be met with would be dust and cobwebs.