You said you were flying VFR.
VFR by Law means clear of cloud and in sight of the surface.
You are also required by law to avoid other aircraft on the see and avoid principle and in addition you are responsible for your own terrain seperation. It follows that if ATC clear you through controlled airspace at a certain level it is YOUR responsibility for terrain and traffic seperation.
Even flying IFR never trust a clearance always always check that the cleared level is safe.
The fact that the FAA advise all American crews flying IFR never to assume that a cleared level in the UK is safe is an interesting point.
I say keep all departures and arrivals procedural. That way we only have ourselves to blame.
I also think that the UK ATC is the best in the world. When I arrive back to UK airspace and call London after a 12 hour flight I know I am safe and sound. 20 years of commercial flying I still say them words "Good morning London, speedbird 068, FL 390 direct strumble" with pride and passion to those guys that keep us safe everyday we take to the sky.