Sorry to revive a thread from two years ago regarding Oscar Egg.
The mixture of French and Imperial threads puzzles restorers but I may have an answer.
Some years ago, a very desirable 1939 Oscar Egg was sold in an auction at the RAF Museum. The price was too rich for me, but I had already been to see the bicycles second owner, Mr Jones, who had bought it in 1940 from a Belgian refugee. Mr Jones raced it and cherished it. I wanted to photograph and sketch features with a view to correctly finishing my own rather more modest OE which has an estimated date of 1936. Mr Jones had had a stroke and was unable to talk much so I spent an entertaining hour chatting to his wife who gave me more information about Oscar Eggs just before and after WW2. She believed that Hickings of Hayes imported Eggs and possibly other French bicycles. She thought that they came over as bare frames and forks possibly with brakes but very little else. The bottom brackets, she thought, were English threaded because that was what was ordered. Hickings imported other French components so brakes, cranks, saddle and handlebars would be fitted according to your own taste and depth of pocket. I queried the presence of the well known Super Champion derailleurs and she thought that they might have come over to Hickings with the frames. Later Eggs had brazed on brackets while earlier ones had partly clip on and partly brazed on brackets.
None of the above should be accepted as correct without some confirmation, but Mrs Jones' long term memory seemed very impressive. She had been a keen club cyclist since the late thirties and I wish I had spent more time with her and had made notes. My frame, forks and derailleur came from Les Rigden in Brighton and the rest of the bike is a mixture of English and French. I, alas, now have COPD so the poor Egg is not being used as it should be. It has aged better than me even though it is older.