Ann: Change of Director's Interest Notice, page-18

Quote I read a while ago might help here:

'Directors sell for dozens of reasons, but buy for only one'

So yes, he may be selling because he knows something, but the risk of going to jail for trading on undisclosed inside information is a pretty powerful incentive not to do that. Therefore it is just as likely that any other of the dozens of reasons for selling is likelier.

As an aside, my favourite one recently was Maurice Blackmore from BKL selling shares 'to pay for a new yacht'