Mike Lyle wrote:

I've got the use of a roller,
so I'm going to use that to level it.
The soil is a little heavy here,
perhaps because there has been a phenomenal amount of rain.

Whoa, there! The roller is a bad idea, especially on wet heavy soil: it
may give the appearance of levelling, but I reckon the high spots will
pop back up in due course. You also want a rather loose tilth for the
turf to get its roots into, not a compacted surface.

Thanks for the warning.

Actually the soil is very dry at the moment,
as the temperature here (Tuscany) is around 30,
and there hasn't been any rain for a week or so.

The roller is quite light,
and didn't in fact seem to have much effect.
I'll rake the soil before laying the turf,
and maybe even fork it over.