Ditchjumper2 - the guys (and girls!) had a great day - it was an expensive couple of days for them, but there would have been no way they could have done it any other way.
It depends how much you value your hunting - a day's visitor's cap plus hireling will be several hundred pounds - but you get a perfectly behaved hunter who is fit and ready to rock and roll, presented to you at the meet. No time spent "making" a young horse over several seasons into a mannered ride, no wet, cold, dark winter mornings slogging away getting them fit, keeping them fit etc etc. If you think a good hunter costs say £8k to buy and say £4/5k to run - that's a lot of days on a hireling!
(figures are very ballpark and are mainly plucked out of the air! I know it's possible to buy and keep cheaper, but I was equivalating the type of horse provided as a hireling in a decent country)
(No research has been done in the formulation of the above paragraph!)
I suspect it varies around the country, but hirelongs seem a bit thin on the ground around here in the SE. One reputable one that I know of serves a few hunts around these parts but other than that there aren't many around.
I was up in Leics at new year and did contemplate hiring there, £270 for New Year's Day meet I think it was. Didnt go in the end. And the thought of those infamous Leics hedges freaked me out a bit!