How does a private operator establish what the approach minima are if they are not in the AIP and the Jepp minima may be wrong for a number of these airports?
What makes you think that there are RVR/CMV/vis minima for such approaches?
Prior to about 1992, there were no such mandatory minima for private and aerial work flights in the UK. The advice was to use the public transport minima, but there was no approach ban.