The answer lies in the licence privileges. Schedule 7 applies to a UK PPL
(2) The holder may not:
(c) unless the licence includes an instrument rating (aeroplane) or an instrument
meteorological conditions rating (aeroplanes), fly as pilot in command of such an
aeroplane:
(i) on a flight outside controlled airspace if the flight visibility is less than
three km;
(ii) on a special VFR flight in a control zone in a flight visibility of less than 10 km
except on a route or in an aerodrome traffic zone notified for the purpose of
this sub-paragraph; or
(iii) out of sight of the surface;
Now compare that with the EASA licence privileges in Part FCL
FCL.205.A PPL(A) — Privileges
(a) The privileges of the holder of a PPL(A) are to act without remuneration as PIC or co-pilot on aeroplanes or TMGs engaged in non-commercial operations. and
FCL.600 IR — General
Operations under IFR on an aeroplane, helicopter, airship or powered-lift aircraft shall only be conducted by holders of a PPL, CPL, MPL and ATPL with an IR appropriate to the category of aircraft or when undergoing skill testing or dual instruction.
So you will see if you hold a JAA now EASA PPL there is no 3 Km restriction, neither is there any requirement to remain in sight of the surface. You are limited only by the VMC minima.