So he's right about a twenty minute gap and the vantage point, but wrong about when the crime occurred, wrong about the entry point and wrong about Tannerman? That makes his overall theory unsound, doesn't it?
From memory, I would summarise his theory as having a core consisting of the following.
That there is a vantage point to the south of block 4, from which one could monitor the Tapas group, whilst being both unseen and in 100% safety. That from that point, it would be possible to carry out an abduction, with very low risk, for the simple reason that one can monitor the Tapas group nearly 100% of the time.
It doesn't matter whether an alleged abductor used the front door with a key, or the rear through unlocked patio doors.
There is such a vantage point and it is a regular on my tours. From that start point it was possible for a lone person to carry out an abduction, with a high degree of safety and a high chance of success.
I happen to think that key control at the OC was weak, for several reasons. Mr Horrocks appears not to know this.
Mr Horrocks appears not to have scrutinised the time line in sufficient detail, nor has he analysed the pattern of activity of the T9 that week. I have. Accordingly, I am confident there was a predictable window of opportunity when starters began being served. There was a longer window of opportunity which began when the main courses were served.