Ann: Director Retirement, page-19

Is there a period after a director retires that they cannot buy on market of they couldn't before?

It is a common misconception that a director cannot buy on market at many times. The only hard and fast black and white rule is 2 weeks before a financial report is to be released. Other than that, unless a director has specific material information that would reasonably expected to cause a market re-evaluation then they are free to trade. But that is no different to any investor who has material information that is not available to the general public, you cannot trade the company. Now trying to prove this is a whole other kettle of fish.

So in summary, yes, subject to being privvy to confidential information that could be proven in a court of law, Glyn is free to sell or buy as he wishes.