Thanks Lynn.
There are quite a lot of seedlings, way more than I need, and way too crowded to do well without regular thinning. There are a few (with wider, flat leaves) that are growing faster. As you say, I'll need to prick them out (soon) to be on their own and to give the others more room. I'll try to get a pic today.
My problem (well, one of them
) is they are growing really slow at this stage, and I'm terribly impatient. Knowing it's a mix, I want to see what every seedling will turn out to be!