I havent had this op but I work in the NHS so thought I might be able to offer some suggestions.
Have you had a date yet for a pre operative assessment? (POAC). If you do it would be good to take a list of questions you may have. Hospitals are working towards ensuring anyone needing medication at a particular time receives this. Some hospitals have a link nurse or Matron for long term conditions. The hospital should provide some information for you on the operation and what to expect afterwards in terms of recovery. The PALS team at any hospital can help with queries. Patient UK is a good website.
I hope it goes well for you.