I don’t believe that this is an RAF/civvy difference of approach; with both of the airlines I have flown with there is only black and white about the SOPs for visual circuits or anything else for that matter. Indeed, the procedures are far more prescriptive that I was used to in the RAF. So I conclude this is just a GA thing; perhaps for good reason Genghis, as you pointed out the other traffic is all over the shop so one just has to cope.
You may have failed to consider that the average standard at the average flying school/ club is quite low, standardisation is rarely in place or enforced. General civillian circuit discipline is very poor too, put 3 different schools in the circuit and you will get three different patterns. Recently on here a PPL examiner stated that a student downwind should be able to reach the runway in the event of an engine failure. Other folk lore widely preached is that 3 degree glide paths are only for airliners. Another examiner I know says every standard approach must be a glide approach! Over the years Ive worked in 10 different flying schools and in only one of them was there an acceptable standard and that school was run by an RAF wing commander!
Ron Campbell by the way was more influenced by US methods than 50s RAF methods as anyone who knew him would tell you.