The post you are reporting:
Prior to the DHB revised proposal the £20m PDCT shareholding in the new company was locked in and could not be sold, mortgaged, transferred or otherwise disposed of, they were therefore, effectively, of no value except as a very minor voting block at the AGM. One of DHB's revisions is to allow the £20m to be sold or otherwise traded (mortgaged, transferred, etc,), but with first refusal going to the new owners.
This does mean that they have a value in the real world, but it also means that it is no longer an 'enduring' shareholding. This is because when the flow of dividends dries up after 5 years when the new owners transfer ownership of the port to another port, offshore, in the same group, the PDCT will find itself running out of cash fast and will need to raise money through the sale of its shares in order to keep functioning. The PDCT will become just like the Northern Rock Foundation - cashless and defunct - within a relatively short period of time once the port's ownership is transferred offshore.