lettuce sowing now

Still time to sow calabrese for the late autumn and kale for winter. Maybe a few late carrots.

Also chicories for radicchio such as Palla Rossa types, and any kind of endive.

Parsley for winter use.

Last sowings of lettuce, I like cos ones for autumn as their upright habit results in less mildew.

But I think you are a little early for lambs lettuce as it often gets mildew when growing in dry weather, unless it is going to rain a lot in September!