Trying to ignore all the rubbish in the article, there are still points to learn from it.
Garbling (label overlap) is a problem. So why do NATS pursue a policy of minimal flow restrictions and therefore maximum airborne holding ?
Stack delays could easily be managed at 10-15 minutes yet anytime the landing rate at Heathrow is reduced (eg strong winds) EATs are allowed to increase above 30 minutes, filling every inner and outer hold and exacerbating the radar garbling problem.