its harsh but then for them to take your idea and tweak it is a great compliment of your work. Its hard to except, but unless kestrel want to get in to litigation with them, its not worth wasting your energy over. Was either design ever registered/protected?
I actually think on the first example they improve the look of the detailing. There is an inherent influence of products we take in around us, and if a company does something unique you can bet there is queue of company’s who are happy to take that idea and tweak it to make it their own…just look at some of the footwear posts.
I had a similar instance of a component we had custom made to my design was then used in a competitors machine by the supplier…sigh