There was a post in the last few weeks about someone who was looking for a water inlet hatch cover that would lock. They had found one in white; however, they were looking for a black one.
I've searched with every keyword that I can think of over the past couple of days looking for the post, then I followed up with a manual walk through of sections and posts and could not find it. So I apologize for creating a new thread, hopefully if the thread is found, the mods can move this post.
I was in my local RV parts center (I don't always get a chance to be unaccompanied in there, kind of like going to home depot!) and I saw a black hatch cover with lock. Remembering the thread, I took note of the manufacturer and when I got home, did a search. Low and behold, they have lots of options. Their website is here -
https://jrproducts.net/product-categ...hatches-fills/
So if you haven't found one yet, you just need to hunt one down