Did the Ten Year Rule imply war in 1942?

Would the Royal Navy switch from broad research to mass development in 1941 because the Ten Year Rule pointed to war in 1942?

No. The rule's end removed an assumption of ten years' peace, but only an actual major war would trigger the wholesale shift toward development.

Ending the Ten Year Rule did not create a firm 1942 war deadline. It meant planners could no longer assume ten years of peace, not that a major conflict was certain in that particular year. Shifting money from research to mass development in 1941 would leave the Royal Navy behind if war waited until 1949. Minor conflicts would not justify that wholesale reallocation, so broad research continues until a major war creates immediate pressure to field selected systems.