I have a small lawn in the back garden. Two thirds are overshadowed by large trees. I laid turf 2 years ago and now the grass is very patchy, like my thinning hair. I get many leaves falling onto the grass in the autumn. I tried to get as much of the leaves off as I could. I want to reseed but I don't know what type of seed to but. How shall I lay it and will it be safe for my cat?