Posted: 10/12/2015 at 11:05
Others may disagree, but I'd aerate it then give it a moss treatment in the spring and a thorough scarifying/raking when that's worked, to get rid of the dead stuff.
When the ground has warmed up I late spring I think I'd scarify again then scatter some general purpose lawn seed (preferably just before rain is forecast for the next few days). Then leave it alone for a while - no fertiliser for the summer - once the grass seed has germinated mow once a week on a med to high setting.
A leatherjacket nematode treatment in August and perhaps just one specialist autumn lawn feed in October.