Two points.
If one does not have a valid IMC or an IR then why would one want to practice an IFR approach procedure unless acompanied by an instructor who would be teaching you how to do it? Is this a case of practicing something that can't be done for real and if so then why?
If the instructor is in the aircraft then going IMC/IFR for a period during a practice approach eg Chilli vectors you into a cloud is no problem. Thus in this respect, I agree with the CAA and Chilli's view - don't practice IAPs unless your flight can accept being IFR, IMC at some stage.
US ATS philosophy, built around class E where IFR is assumed to be able to see and avoid random VFR traffic
That is worldwide ICAO and UK philosophy in Class D E F and G airspace i.e. IFR flights in such airspace should be able to see and avoid VFR flights and vise versa hence the VMC criteria, speed limitations and lack of a requirement for separation.
Even in UK Class G there is no separation provided regardless of service received - Even RAS is Advisory and separation is not guaranteed for a number of reasons.
US IR holders flying N reg aircraft in Europe must comply with the US rules for the number of approaches, VOR check etc etc to fly IFR, unlike their UK cousins flying G reg who can fly IFR in a piper cub with a map and compass!
This leaves the US IR holder who does not fly IFR reguluarly in a bit of a pickle by having to bag lots of instrument approaches and having to pay the practice approach fees at various fields. Of course claiming to be VFR could avoid such charges and also enroute charges if the aircraft is heavy enough. Not unusual for French Authorities to complain to the CAA about aircraft claiming to be VFR departing into IMC enroute to the UK!
Regards,
DFC