Mr G wrote:
I had a lawn laid about a year a go and it is very bumpy. I rolled
it several times after laying but this had little effect. I know I
should be calling back the idiot who laid in the first place but is
there something I could try myself? Previously I hired a roller
that I filled with water but this did not seem very heavy. Are
heavier, larger rollers available and would they be any use to me?

'Don't think rolling is the answer. I know they roll cricket pitches
but they end up bone hard and bare and need constant watering.
If the humps are discretely obvious and few in number, I would slice
round three parts of the hump, take out some soil and redistribute
that in the next hollow. Otherwise I would suggest a generalised top
dressing of the hollows with top soil - a little at a time so as not
to create big bare patches.
It will take a surprising amount of top dressing to level a lawn but
short of taking it all up and starting from scratch and doing it right
next time, I don't think there is an easy answer.

--
ned