They are not "reporting points" in the VRP sense. They are used as IFR waypoints.
No way should UK ATC ask or expect
VFR traffic to navigate to or report at any of them, because the only way to navigate to them is with RNAV i.e. a GPS, but GPS does not officially exist for VFR
(In some countries VFR traffic
is expected to navigate via IFR routes - e.g. Greece).
In general terms, ATC should be familiar with those local to them; e.g. VFR traffic inbound to Bournemouth could report at NEDUL, though more traditionally it might report at The Needles (almost the same place). NEDUL is shown on the VFR chart.
London Information is also familiar with them, especially those on the FIR boundary with France (and they can see you on their "unofficial radar" these days).
IMHO, and ATC will always deny this because they must, if you ask for a transit of some CAS, giving your route in terms of IFR waypoints is more likely to get you in because it sounds more like you know where you are
More practically, if you have them loaded into a route in the GPS, you should be able to read off the ETA to any of them instantly, which is another great cockpit workload saver.
I think that if they were all shown on the 1:500k VFR chart, they would clutter it far too much.