You might want to look through this recent thread. https://forums.chiffandfipple.com/t/cracked-fipple-issues-on-freeman-whistles/86912/1
Yes - was there a solution?
My smart phone is not working so no camera…sorry! FWIW I have already repaired the blue top gen D with thread and fingernail polish. However, I did read the thread about all the cracked whistle-heads. Seems to be cause unknown? I’m now thinking its a matter of ware and tear so to speak of everyday use. I take them out of the tube(cardboard mail tube) then, put em back in…twist and turn to tune or move the mouthpiece back and forth. Apparently, it doesn’t take much of this to crack them! Sad to say. 
Well! I’ve solved the problem…I’m in the process of doing the thread wrap & fingernail polish trick to all my whistles. Not my low D tho…which is a PVC whistle. 
Hmmm. Some general maunderings. . .semi-coherent. Plastic looks like a solid, but thermo-plastic plastics in particular are not. They’re not really stable in the greater scheme of things. A look at the famous “Pitch Drop Experiment” will get you into the right frame of mind. The bright young men in the injection-molding biz are always tweaking their formulae and not really thinking in terms of years of service.
Bob
Bob, I think you are on to something with this line of thinking!