Cheers again for all the comments! I had shared these photos with a few friends and other explorers and there wasn't that much interest so it's a nice surprise.
The horse drawings are there as they used to cart the stone out of the mines along with the oxen. You can still see the grooves the harnesses have worn into the corners of some of the tunnels. In one of the deeper sections of the catacombs we also came across some of the underground chambers used as stables. The only way you could tell what they were was from the dark brown soil in these chambers that could only be created by years and years of horse shite!
If anyone is ever in Kiev, Odessa is only an overnight train away so it's pretty accessible. I'd definitely recommend a trip there anyway, apart from the catacombs there's also shit loads of other stuff to see in Ukraine, it's a serious spot!