Hi UK Guys
If you live in or visit the far SE of the UK, I have found a barber here in Canterbury who will do head shaves. Its not the closest I've got it myself, but it is certainly passable and a very relaxing experience.
The barbers is called "Kent Barbers" and is in St Peters Street, Canterbury. They charge £10 for a head shave, and charged me £16 for a combined head and face shave.
Hope this information is useful.
Tony