Very grateful for all help with these three clues please.
18ac: "School head comes round with toiletry (7,4)." I have ----I-G, -O-M.
27ac: "Slow month on railroad, with terminally tiresome speed (10)." I have -E---E-A-E.
7dn: "Carriage circles a bay tree (8)." I have C-L---S-.