Apologize for the delay in getting back to this post. In 2018 I purchased 2 struts for my Heki 2 from SGS Engineering (UK) Ltd, 1 Westside Park, Belmore Way, Raynesway, Derby. They were very pleasant to work with and shipped direct to my home in Kansas. The cost for two including shippiing was 48.43 pound sterling which at the time equated to $64.02 US. ($1.92 Citicard transaction fee). I just checked their website and they still have them, part number NL 5030 which you can find under Gas Struts/Gas Strut Application/Roof Light for 20.39 pound sterling. Hope this helps someone in the future looking for parts.
I forgot that this company only sells replacement struts, so sorry no help for the other many breakable parts.