I refer the honourable person to the CAA Safety Sense Leaflet entitled 'GPS'
and the reference that this organ has the slightest
legal significance is......... where?
This is the problem the CAA is now facing, when they try to drag themselves kicking and screaming into the late 20th century.
For as long as I've been flying (~ 10 years) they have had various staff members (both inside and outside CAA premises) emitting their personal opinions and prejudices, in various publications, and in CAA "safety" meetings, all dressed up to look very "official".
Together with the highly deferential climate which prevails in GA (a bit like our whole society was in the 1950s and before) and the almost totally opaque ANO, this stuff has been taken as gospel by many otherwise perfectly intelligent people.
Now the CAA has a double hill to climb on GPS approaches: these need full ATC, and way over 90% of private pilots are convinced GPS is illegal, the work of the devil, etc. Most of these are long-term PPL holders who are operating outside of the PPL training scene and there is no real way to re-educate them.
In the meantime, NATS (to their credit) has got fed up with the constant stream of major CAS busts (a few hundred per year) which only by sheer luck have not yet brought down an airliner, grabbed the bull by the horns and have sponsored the production of a
£150 GPS which runs a decent map.