We have deaf ancestors who were at schools (Asylums) for deaf children in the 1870-80 period. One started in the Old Kent Road, London and later moved to Margate where it still exists -The Royal School for Deaf Children. The other started in Brighton, Sussex and still exists -now at Ovingdean Hall. Both have web-sites, keep early records and are very helpful. Remember they are functioning schools and very busy. They also feature on the census records. Hope this helps.