patch lawn

hello

i planted a new lawn nearly 2 years ago and although its looking ok it seems to be suffering from areas that are looking pale and the grass grows very slowly.
The other thing that i have noticed is in winter the whole garden goes yellow and looks like it is dying!!!!!!
I have scarrfied, raked, fed., and fed again.
The only thing i think it might be is that the soil the seed was planted in was very poor as it had been under gravel for about 5yrs.
Please help, any suggestions?????

 

hi,
There was large chippings 4" deep with a fleece liner under which we removed and dug over.There are no roots as they were all removed.The areas which are struggling look almost like dying grass and although the grass does regrow it stays really fine and very short (1cm)max.The groubn does go rock hard though because its always windy.
Position is full sun