Gary
The option of the port remaining a Trust Port is not dead but it is highly unlikely in my opinion. Why do I think this? As others have pointed out whilst the Ports Act 1991
http://www.legislation.gov.uk/ukpga/1991/52/contents remains in existence the opportunity for Port Management Boards to sell the Trust Port is ever in the background and as such the long term likelihood of it remaining in public hands is low; particularly in the current climate. Further the Modernising Trust Ports scheme
http://www.dft.gov.uk/pgr/shippingports/ports/trust/goodgovernancesecondedition.pdf appears to have at its heart the premise of selling ports. Clearly given the current crisis and the fact that the Minister for Transport did not rule DHBs approach to sell the port out at the earliest opportunity suggests that the government is minded to sell.
Of course as you suggest there are British Port operators who might be interested in acquiring the Port under the DHB proposals, though given the current economic climate I am unsure as to the viability of them doing so. The inference from the pronouncements of the DHB suggest that they do not see this as a viable option and are lining up their golden parachutes with a foreign entity.
I like you and others would like the port to remain in some form of public ownership, but do not imagine that the only option to achieve this is via the state (i.e. remaining a Trust Port). There are other options to public ownership such as the proposal by the DPPT of an Industrial and Provident Society, or alternatively a Community Interest Company might be used as a similar public ownership vehicle. The real difference between the first one and the latter two is that with the latter ones ownership is local and it is local people who will decide on the major strategic decisions affecting the port; something I whole heartedly support.