We have laid a new lawn about 3 or so weeks a go and everything is
coming on nicely. Its still establishing and getting less and less
bald. I assume that using a roller (not too heavy of course) will aid
it to bush out and get thicker ????

My question is when do i do my first cut on this new lawn ? the grass
seed that has germinated is around 2 or 3 inches now and growing
strong. Would cutting it soon but too early or would that aid in
bushing it up to fill the bald spaces that having germinated quite so
strongly ?

Any advice most welcome .