Just thought I would add this as I think I have some more information this afternoon. Floral tributes have been left at the woods I have shown with the white arrow in the map, I am assuming based on this (but I don't know for certain) that this is where Frankie's body was found.
The red marking shows a public footpath. Based on personal knowledge, the path is often/usually impassable due to flooding these days. I don't believe that it is regularly walked. This location does make me think that suicide is the more likely case here. If I am correct and this is where Frankie was found, it's heartbreaking to think that after so much time was spent searching quite lonely areas, he was so close to people. I think he had friends living just across the road, overlooking these woods. To my knowledge, these woods were never searched by police despite being just over a mile away from Frankie's last known location. Sadly I believe there was another suicide in the woods at the beginning of the footpath a few years ago.
A desperately sad outcome no matter what the exact details are. RIP Frankie.