I'd have thought that there was quite enough in the public domain to determining the educational standards of an ATPL.
Re: 3/4 year degrees. In England and Wales the A-level system involves a small number of specialist subjects over nominally ages 17&18, plus the degrees are (compared to many countries, not necessarily Scotland), generally very narrow and specialised - allowing the material to degree level to be covered within that time.
The 2 year degree options are undoubtedly very intense - although primarily what they do is eliminate the long vacations which exist in pretty much any degree course worldwide.
The UK MSc does something similar - typically it's 13 months full time which seems very short compared to the rest of the world; in practice the rest of the world would probably do 2 years but about 8 months of each year - so in practice about 16 months: a little longer than the UK, but not massively so.
In my experience the "shorter" UK degrees are generally academically comparable to those from anywhere in the UK with perhaps one exception - the UK PhD at 3 years is incredibly short compared to much of the world which would rarely award a degree in under 8 years. To some extent the UK simply sets incredibly high standards, but also it omits a lot of the content of many (e.g. American) Doctorates and the *minimum* standard in the UK is perhaps a bit lower at graduation.
(Of course, with pretty much any degree, it's what you do with it - the professional experience, which really matters.)
G