Shortround6
Major General
The Whirlwind was proving to be troublesome, they couldn't wait for the Typhoon's development and they had a solid option before them.
Sure, make more Hurricanes, but if Boulton-Paul had an assembly line ready aircraft, then why not?
We may be mixing up the time line here a bit. The Whirlwind was a bit late in showing up ( a mark against Petter doing much of anything else) and the troubles don't really start to show up until the summer of 1940 which is a bit late to look for alternatives.
The single seat Defiant may have been a lot closer to production ready, just don't expect much difference in combat results than the Hurricane. Also don't expect much in the way of future development.