19A - Like members of Conan Doyle league; I have RED?A???? - I assume redhaired.
27A - Tyre change required by him in 677 BC (4-6). I have ???R?A?D?N
7D - where old major invited revolution (6,4) I have A???I?F???.
8D - madrigalist curiously met no opera composer (10); I have M???G?E??? - help ?