All you had to say is sorry for not crediting people. I take pictures but if someone took one of mine from six years ago and published it as their own, I'd be very annoyed. It doesn't matter age, copyright still exists.
The mod was simply a sub-mod with some new content but with the map hardly changed. I'm sure a lot more effort could've gone into it but you've decided to end your modding here with Welfordshire (V1, although there was never a V2).