Ours are done late autumn, hollow cored, then a later verticut (a civilised form of scarifying) and sanding. Noticed today they've been treated with whatever iron compound they use to promote growth. Be a few weeks yet before they're at their best. Mid to late summer they'll be hollow cored again but with a fine "needle" that doesn't entail taking them out of play.
We do need a bit more sun and more warmth though. Start of April and we had frost last night so some of the greens that don't get a lot of sunlight were taken out of play for the day. It's still cold now and we're forecast for -4C tonight ...