You're really lucky. I got a nice tect from the CEO of 3 telling that I was now going to get 4G here in London for FREE from them. I resisted the temptation (didn't want to kick any gift horses...) to say that I would actually be quite grateful to get 3G which lasted for more than a few flickering seconds here in the centre of London. I travel regularly along a route that includes Hackney, Shoreditch, the City, the West End. At most I get H+, and that not all the time.
Since his kind email I have not once seen the tiniest flicker of a 4 on my S4. A friend who is with O2 sneers at me - she regularly gets 4G.
Great to hear that you can get it up in Walsall. Enjoy.