... your experience is very similar to mine. I had a target of 4kg to lose after seeing nurse and after a year of cancelled appointments I finally had follow up appointment in Feb this year. hadn't lost any weight but hadn't gained either, but as they had messed me around for so long with appointments, agreed to send me for an endoscopy, which will be your next step if you are having the bypass. I had that 21st July, and had lost 5kg so agreed to put me on list. Now awaiting appointment for surgery, which they said would be 4-6 months so should have it done by end Jan.
I think things are speeding up at Sunderland now, so you probably won't have the chew on that I've had.
good luck with it all !!
xxx