Dad had blocks to expand her jaw in year 5/6. Her overbite was about 10 mm.
At the end of year 10, she had her wisdom teeth out. A few months later, braces top and bottom. Six months later, she had her bottom jaw broken, realigned and brought forward. She had a bar implanted cross her bottom front teeth.
Mid year 12, she had her braces off. She has an Invisalign type retainer to wear for the rest of her life. She needs the retainer to keep her teeth in postition because while the teeth can be moved around with braces, the shape of the tooth socket doesn’t change and the teeth will always want to settle back.
All this work, apart from being cosmetic, will hopefully insure her against old age where the jaw will shrink and the gums will shrink resulting in her bottom teeth hitting her top gum and causing problems like ulcers.
As an aside, and I don’t recommend this as a normal solution, but dd found it almost impossible to swallow tablets. X-rays showed her throat space was very narrow. Post surgery, with her mandible brought forward, her eosophagus was able to open up (almost double in size) and tablets are now no problem.
Sorry, not in the UK.