I hope they can piece together those missing hours too, that could shed some light on why he went to Loughton, with no jacket, in very cold weather.
Also why he took a taxi instead of using the Central Line. He doesn't seem to have been cautious of using public transport from the point of view of his health, but he may have had security concerns (mugging in particular) travelling alone on the underground network.
I think turning around in the last final CCTV image might be some nervousness, about making sure he wasn't being followed. Yet if he had arranged to meet someone who wasn't a usual friend, in the forest, that is quite bold. I'd like to know if he was familiar with the area, as he doesn't seem to have his phone out.
Listening to that interview with his mum I think she tried calling him the following day. I see references in this thread to his phone going off at 10pm but was that the following evening or the same evening? I'm thinking he might have paid for the taxi using his phone, after 10pm. Unless he got to Loughton before 10pm and spent three hours or so there before he was seen on Smarts Lane.
All IMO