Here's you answer:
"A possible reason why the rates of surgery are so low is that U.K. general practitioners cannot refer patients directly to surgical services. Instead, there's a "tiered pathway" that patients must go through, starting with social interventions to enhance weight loss (food taxes), then lifestyle interventions with the guidance of a primary care physician, then secondary care including medication, and finally referral to a bariatric surgeon."
Once you are referred to a surgeon, your wait for an initial appointment can take months. Then, you might not even be put on the waiting list at that appointment. So a year down the line, you are put on the waiting list, which can take between 6 months (haha yeah right!) and 2 years.
I was lucky, very luck that I got in before the tier system came in. I still had loads of shit I had to do and deal with, but nothing like the folks do now :/
So to break it down, you decide to have WLS, wait 2 weeks for GP appointment where they refer you to weight management. Getting an appointment for weight management can take 6 months or more. You can be stuck climbing the tiers for 2 years. Then you finally get referred to a surgeon where getting an appointment takes MONTHS. Then a possible 2 more years til surgery.