The Jump Hole to Newcastle has been located. After a very thorough search in Manchester, I managed to follow a Bretonnian Armed Forces patrol. They passed a jump hole to "Salisbury" or somewhere, then to the Newcastle Jump Hole. A group of Gaian ships emerged from the Jump Hole and annihilated the Crusaders. I was thankfully out of scanner range, hiding in a small cloud of dust.
Here is a picture of the jump hole. It is located in 4.7 C.6.
After locating the Jump Hole, I activated the jump sequence to explore what was on the other side. When I emerged in Newcastle, a group of Mollys were attacking some Bounty Hunters. I moved to assist but my ship was atomised by a nuclear mine. The Molly leader tractored my escape pod in.
The Mollys eventually won the fight and brought me back to Mactan. I told one of them my assignment, and he gave me a map of the Barrier Nebula in Newcastle.
From what I saw, the jump hole is a common pathway for both the Bretonnian authorities and pirates. During my intel gathering, my scanners showed Bounty Hunters, Gaians, Mollys and the Bretonnian Armed Forces patrolling or using the anomaly.