Hi again,
With regards to my earlier posting - I have managed to speak to someone who knows the history of the Park quite well. It appears that there was not a burial area within the Park grounds. People who died at the Isolation Hospital were taken off site and were usually buried in the grounds of Moggerhangar Church, although sometimes in Everton Church or Northill Church which were nearby. In a few cases other Churches were used within a five mile radiius of the Park.
Maybe still worth contacting the House Preservation Trust, but the nearby churches could be a possibility.
When I last visited the Park, about four years ago, some of the old Hospital buildings are still standing in the grounds including at least one of the wards.
Steve