Hi everyone, I have been reading all comments and I am learning so much from it all.
I think I can now clear this up after a bit of reading.
To remain VFR above 3000' AMSL you do not need to be in sight of the surface and below 3000' AMSL you do need to be in sight of the surface and if flying less than 140kt IAS you can fly in only 1500m visability.
However the 'privileges' of a PPL are different.
Basic PPL;
Minimum flight visibility 3km
Remain in sight of surface at all times
Minimum visibility 10km and in sight of surface on an SVFR clearance in a CTR
Flight in circumstances which require compliance with IFR not permitted
PPL with IMC Rating;
Minimum flight visibility 1500m to maintain VFR
Minimum flight visibility 3km, clear of cloud, and in sight of surface on an SVFR clearance in a CTR
Minimum visibility below cloud 1800m for any take-off or landing
It is safe to assume that you can fly VFR on top if above 3000' but not with a basic UK PPL.