SueDublin being in Southern Ireland is not actually in the UK! If you are staying in Dublin though, I understand the Harcourt Street Children’s Hospital is a good place for CAH care and the paediatric consultant there is a Professor H Hoey.
There are about 20 paeditric endocrinologists scattered around London, so wherever you stay there, you won’t be far away from a hospital that can help. Let’s hope your son stays healthy and won’t need to visit any one of them though!
Enjoy your trip!