Again, unless I've misunderstood, there's no CCTV covering the path between the gate and the bridge on Blackpool Lane. She could have walked out the way she walked in. But without her dog and her phone..
Ah, when the police said there was only one route not covered I thought it must be where the broken camera is. So she could have left westwards towards the main road? It would be difficult for someone else to take her that way though, without being seen?