In article , P tonyno_blood
writes
I have a lawn which is approx. 4 years. This has been a great success,
self seeding, hard wearing etc. However, every spring the lawn becomes
uneven, so is it safe to assume that it requires rolling and when
would be the best time?

Never roll a lawn - it just compacts the soil underneath it.
The best thing to do is level off the lawn by putting sharp sand in the
hollows. The grass grows through very quickly and you even it all off
when you give it the first mowing.

--
Jane Ransom in Lancaster.
I won't respond to private emails that are on topic for urg
but if you need to email me for any other reason, put ransoms
at jandg dot demon dot co dot uk where you see