Popping your ears isnt a great idea. It can perforate an eardrum.
Reading this thread now it has been reactivated is interesting. The diagnosis of fluid behind the eardrum, known to doctors as chronic otitis media, is simple - you look in the ears with an auroscope and see the eardrum is dull. you dont need an audiogram!
The medical treatment is decongestants such as actifed, antibiotics possibly and painkillers if necessary. Unfortunately the key is the decongestant which you cant fly on. This treatment also takes time, and meanwhile depressurisation carries a risk of perforation of the eardrum - this doesnt kill your career, but may need an operation to repair is so you are grounded for months
Hot water, oil or anything else outside the eardrum is a waste of time - the problem isnt the drum but the drainage tube which is miles away.
The other treatment is to drain the fluid by a small nick in the eardrum. A washer or grommet is often left in so the ear can drain and you are soon fit to fly. In many countries this is done with some local anaesthetic in an office and takes perhaps 5 minutes! Whilst I agree the NHS doesnst usually consider this an emergency, if your career or health are at risk - ie you cant fly or you fly and perforate your eardrum - they probably will. If your ear is painful it is also urgent. So the morale of the tale is if it doesnt settle rapidly and you fly for a living, make a fuss, demand to see an ENT surgeon, and demand some grommets.