Posted: 15/03/2016 at 07:52
I think you can restore that. We had a similar problem after three builder's skips spent the summer on our lawn a few years ago. Now you'd never know!
Use a lawn moss killer (according to the pack instructions) to kill the moss - when the moss is black rake it hard with a lawn rake to get rid of it and put it in the bin (not compost heap). Give the surface of the area a good roughing up with a rake and spike it all over several inches deep with a fork to get rid of any compaction.
Then rake the whole lawn - sow grass seed on the bare patch and sprinkle some of the same all over the rest of the lawn. When it grows it'll all blend in together and not look so much like a patch.
Sow the grass when the soil temperature has reached 9C - grass seed germinates between 9 and 12 C.
Good luck - hope that helps.