This is a tricky one because both P. natalensis and P/ sebae occur in the DRC. I also spent some time there and only found natalensis.
Having said that, this snake looks more like P. sebae. I say that because of the dark, broad patch in front of its eye, which natalensis lacks.
Very cool of them to let it go healthy. All the ones I found were killed and eaten
"I am dying by inches from not having anybody to talk to about insects." - Charles Darwin