Another point to note about the UAS system is that as well as helping to select descent potential officers for the RAF, it also helps to "weed out" people who are completely unsuitable. People who cannot spell or punctuate, for example. Also the Top Gun groupies who introduce themselves as Maverick and then puke up on trip one.
During my time, I met several folks who were initally keen to pursue a career in the RAF but after even the limited amount of exposure that being a UAS cadet offers, decided that it wasn't actually what they wanted. And then left. That saves on the cost of sending someone through training post IOT earning £20000 per annum when it can be done pre-IOT for cheep beer and a free lunch once per week.
So anyway, in response to the original thread, I think that UASs represents good value for money in the big scheme of things. For each pilot that joins, the saving in pay alone must be >£10,000. About the same for someone not starting IOT when they are obviously not suitable.