Falcon Industries, New Zealand, used to make a Clear-Vax vacuum formed canopy specifically for the 1/72 Airfix kit. I bought mine several years ago as part of their 1/72 scale canopy set No. 1 - U.S. Navy World War II. It includes canopies for 12 different 1/72 navy aircraft kits including Airfix, Frog, Monogram, Heller, Matchbox, and Hasegawa.
I think that these canopies are also available individually, although you may have difficulty locating one for the Kingfisher because it may be long out of production because of its age.
You might want to search various model suppliers around the web or contact Falcon Industries directly. The instruction sheet says that Falcon Industries is an associate member of IPMS New Zealand. Let me know how you make out.
Pete