Orford Ness and Blue Danube
 

Intrigued to read that Lancasters (modified) dropped the first Blue Danube inert bombs on the ballistics range at Oford Ness. Author claims several dozen casings in sea off the ness. Anyone remember these trials?

Perhaps "modified Lancasters" refers to the Lincoln? According to Wiki/National Archives these were involved in developmental tests dropping the Blue Danube casing:

"Lincolns were frequently employed as testbeds in new jet engine development. RF403, RE339/G and SX972 flew with a pair of Armstrong Siddeley Python turboprops outboard in place of the Merlins, and was used for the ballistic casing drop-test programme for the Blue Danube atomic weapon.[29] "

The National Archives, London, file ES 1/44