Hi Michael,
The Heysham to Belfast route has been bought by Stena, along with the ships. As far as I know Stena does now own the route 'fully', although there was some interference by the monopoly's commission. They did however paint the Stena livery on about a month or two ago, so I would imagine that the ships and route have been fully secured.
Jack.
P.S. See attached a picture I took in Heysham some time last month.