I tried to help...but when I looked up "sindewatch" in Google...most of the links are East Indian porn links.
https://www.watchuseek.com/threads/vintage-watch-manufacturers-brands.984991/The watch brand is listed in the OP's post.
Noticed...and if the folks on that forum knows little to nothing about the brand...nobody will I fear. I am thinking it must be one of those boutique short lived watch makers. You could always make a post on that forum and see if you get something. I fear I got nothing for you on this topic.