If you were born with a cleft you have a right to go back for further reviews/treatment at any time, no matter what age. Specialised services should also have access to a restorative dental consultant who would have specialist skills in constructing prostheses for cleft lip and palate patients. There is a completely new system of cleft care in the UK that has been developed over the last 12 years and there are now specialist regional cleft centres which see large numbers of cleft patients each year. You should ask your GP to refer you to the nearest one or you can call them yourself and self refer.  There is a complete list of centres at http://www.clapa.com/medical/treatment_centres/