weight loss surgery

I am being referred for weight loss surgery on the nhs after years of fighting my weight. I was diagnosed with asthma when I was 11 and also a hole in my heart and have been on steroids nearly even week since I was 11 am now 26. since having my son 2 years ago my weight has went up a lot also because I have pcos which has been extremely hard desperately wanting another baby but won't at this weight I am currently 20st since being on steroids before that I was a size 8 . I have Been struggling to be referred for this for the last year and it's finally happening was just wondering if anyone els has had surgery on the nhs and how long they wanted from being referred to having the surgery. thank you