Just as Irv says. Very easy. I flew here for quite a lot day VFR on my NZ PPL, having demonstrated to the school I hired from that I could actually fly. Navigation was another issue altogether. When you learn at Wellington as I did, there are plenty of ground features to point you in the right direction... Less so near London when one town looks and sounds like another, at least for a while.
Then I converted to a pre-JAR PPL. Easy. GFT (General Flight Test), HUman Factors and Air Law I think. Can't remember really, but it was a doddle. Conversion allowed me to venture outside the UK in a G-reg aircraft.
Enjoy.