He is simply conforming with CAA advice that VFR flights are recommended to fly at quadrantals in the circumstances IFR would require compliance).
In the context of a CAA vanilla PPL the actual operation of an aircraft under IFR and VFR is virtually identical (the only significant difference is quadrantals are mandatory under IFR and recommended under VFR), so most UK PPLs don't really think about it (and I suspect most in their minds are VFR).
However, the bit I hadn't thought about is - A UK PPL was broadly exempt from the cloud clearance requirements of VMC above the TA as he could just as well be IFR (but clear of clouds and with the required in flight vis). It appears that JAA/UK PPLs do not have this privilege and must (like all other PPLs) remain in VMC (in the full sense of the term) as all times.