The five hours figure is achievable, depending upon the individual of course. There are actually two separate flight tests - a navigation skills test (NST) and a general skills test (GST). There's no need for phone calls - it's all just a click away
here.
On the larger and more interesting question of whether the UK-only NPPL SSEA is worth doing (for those who have the choice and aren't restricted by things like medical issues) I think that
IO540 is right. The limitations can become frustrating very quickly. A simple illustration is that you will generally need an ICAO licence in order to hire aircraft in other countries and the NPPL SSEA won't do.
A Europe-wide recreational licence might change the balance, but on the other hand an achievable UK IR would change it back again. IO's basic point of not saddling yourself with unnecessary limitations that later might need to be undone is a very valid one and worth thinking about carefully before committing to any particular route.