Constrictor defiantly got BSA to make their pedals and hubs and their pre-war alloy cotterless chainset looks suspiciously like a Stronglight. Chater Lea made their own hubs. I was an apprentice in Letchworth and Chater Lea's were just around the corner. We did most of their printing they were miserable sods to us apprentices when we took the printing proofs around to them. One of their employees told me one day when I was waiting for them to pass the proofs, that they had contracted out to Williams to supply them with Chater rings. Apparently these CL rings turned up with the Williams mark on the back and the old man had to put them all on overtime to grind this off before they went to their plating shop. Bet this pleased him they were known as tight sods in the local engineering trade .
Best wishes and be lucky. Michael Butler Huntingdon UK.