Operations by O.T.U.'s

Attached are two pages from my Father’s Logbook, the entries being made when he was with 14 O.T.U.

Attachment 1 shows that on 12/5/1941 he participated in a trip in a Hampden of 4.25 hours endurance. It is logged as “Raid 1 Alternative.”

Attachment 2 notes that on 11/6/1941 he again participated in a “Raid 1,” this one being of 3.30 hours endurance.

My questions are, what exactly is a “Raid 1 Alternative?”

Is it possible to discover where they went on these alternative raids?

Did all O.T.U.’s participate in such “practise” raids?