Yes, absolutely Greatnan. My guess is that, as a life sentenced prisoner, his behaviour going past the tariff date has been so extreme as to concern different parole boards. Every time parole is refused, a further statutory date is set and requirements for progress imposed on both prisoner and prison staff. The same panel will not review parole applications each time. Many different parole board members will have looked at the case, including lay members. I have no idea what would have been going on. Prisoners who don't meet parole requirements don't just get forgotten about. They are moved to other prisons where they can progress. Appeals and investigations are available in case of discrimination.
As we don't have inside information, we can only speculate what information was provided to the parole board, and what he himself would have said about his application, as he would have been seen in advance by many different professionals, prison visitors, campaigning organisations supporting his case, and even journalists who could be given a visiting order. I know one particular Guardian journalist who makes it his business to follow such cases and can be a real thorn in the side of prisons.