Earliest airborne ASW radar was installed in RAF Hudsons in January 1940. On the other hand by October there were only 57 in operation (that is if the original 12 Mk I sets were still around), and by mid-1941 only half of Coastal Command had them. I don't think the game lets a modder be that precise.
http://www.exreps.com/Trojan/Develop...20Dec%2006.pdf
It looks like you're right about the Leigh Lights as well. The first one was tested in March 1941.
http://www.uboat.net/allies/technical/leigh_light.htm