All the answers are birds
12 Air infection (4 6)
18 No flipping score (5 4)
22 Duck found in bed (4)
28 Age of the hog(6)
29 Mix German River (5) Heron fron Rhone isn't right because it's not in Germany
31 Pint after hours (8)
42 Discovered in the Bell Inn, Eton (6) (I already have Linnet for Scored 50 L in net)
Thank you for that quinie - really good answer I hope tha it didn't keep you awake - but Golden Eagel doesn't fit the number of letters - but I like your thinking on the Rhone. Thank you again