Hi Jen,
Here we go:
Frame number 60698 comes from military contract S/2604. This was a contract for 7.000 bikes (frame numbers 72070 - 79069). Production started in November 1943, at 1.600 bikes per month. Which would make your bike January 1944 (approximately). The original census number would have been C5480998. Here are some pictures with close numbers (same contract):
Frame number 60698 is listed in the post war KeyCards, which means that it was used by the BAOR after the war was over. The post war ERM number was 06 YB 30. It was finally demobbed in November 1960, when it was sold off in one of the Ruddington auctions. (Lex can do you a high resolution scan of this KeyCard for a modest sum.) Here are some pictures with close numbers:
The engine with duplicated frame number 56657 comes from military contract S/1050. This was a contract for 9.000 bikes (frame numbers 48060 - 57059). Production started in June 1943, at 1.400 bikes per month. Which would make your bike (or "your engine") December 1943 (approximately). The original census number would have been C5264057.
The engine was rebuilt in February 1945 in the Ministry of Supply "Auxiliary Workshop B193", as can be seen in the additional steps. Check this forum thread for more info.
email (option): wd.register@gmail.com