I think different NHS boards have different referral guidelines?
I was just at the doctor last week for my first medical issue with my (awful, hideously ugly) varicose veins. I have 'thrombos phlebitis' - an inflamed vein. It's right behind my left knee (amongst the mass of veiny awfulness, stretches from mid thigh to two thirds up my calf, right leg isn't quite as bad) and was really quite painful when it first happened, and has been intermittently painful since. And is painful if I prod it.
I'm only 31 by the way, and my veins started when I was 16 
Apparently one episode of this is enough to get referred to the hospital, so I'm waiting eagerly for my letter to arrive now! Although I'm a bit scared at the same time. It would be good if I could get at least one leg fixed, but it's scary to think what it would entail. I can sign up for BUPA through my work, so if they'll fix my left leg on the NHS, I might then get my right leg done privately. Then I could wear something shorter than three inches above my ankle again [dreaming emoticon]
. Seriously though, that would be amazing. The bumpiness now shows through (i.e. you can still see them sticking out) when I wear opaque tights and (even more depressingly) leggings! They really do suck
And they ache and itch and burn etc etc etc.
That turned into rather a long rant about my veins - sorry! 