The only organisation in the UK that would appear to routinely use QFE is the RAF (plus, I assume, the RN and AAC?), although I don't know what the formerly shiny fleet at Brize and the Truckies at Lyneham use.
All datums at significant civil aerodromes are based on QNH and I know of no airline or AOC operator (UK or otherwise) which uses anything other than QNH for visual or instrument approach work. All the charts published (Jepp, Aerad etc) use QNH with heights referred to threshold/aerodrome elevation in brackets (presumably for the RAF). For Nairobi and other similarly elevated aerodromes, I seem to recall that QNE was the most used practice given the limitations of altimeters.
Given that, in a relatively short flight outside controlled airspace, a relatively inexperienced or student pilot, not to mention those of greater experience, can be instructed to fly on 3 or more potentially widely spaced pressure settings QNH, Regional Pressure Setting, QFE, Standard (1013.2) if feeling brave, perhaps another RPS and another aerodrome QNH, the potential for confusion and misreading/mis-setting altimeters with all these changes of setting is, I would suggest, greatly increased.
In these days of constantly updated information are RPS really relevant? These would appear to date from the days of the Shackleton and Dakota when pilots were out of communication for prolonged periods and needed a FORECAST RPS for the areas in which they were operating.
Is QFE really necessary? Even for a Surveillance Radar Approach the controller passing an advisory altitude based on QNH is giving the pilot a figure to which he/she may adjust rate of descent. At Decision Altitude/Minimum Descent Altitude the pilot will take an appropriate action on the basis of that altitude. Seeing zero on the altimeter at the threshold is an irrelevance, as at the threshold it may need to read 50ft or so.
Let's just have QNH and Standard and be done with it. And whilst we're about it let's have a standard transition altitude. Howzabout 10,000ft. So that'll knock it down to a very few pressure setting changes for those unpressurised aircraft operating outside CAS and below 10,000ft.
Standing by for incomers..........