Ah, I see. I thought the "local provider" you were going to see was your local NHS bariatric hospital about their private costs.
I think the advice from the *private* clinic is therefore ******** and emotional blackmail entirely designed just to make you have your original surgery with them.
They are a COMMERCIAL organisation concerned with making a profit ..... I am sure if you turned up to them in 2 years time never having previously met and they discovered there and then that you had an existing sleeve but were now enquiring about revision surgery to a RNY or DS ..... they would ask you to pull up a seat and go thru the options and costs, no problemo !!!