Hi Alan, my number 1 favourite is Tyee which you can use all the year round even in the summer as it is very slow to bolt,but it is a semi savoy.Very mildew resistant
My favourite smooth leaf is Olympia.Again year round sowing.Mildew resistant.
I also like Space.
I have most of my seeds sent from overseas but e seeds are good ,they are here in the UK and bring in a lot from the US. I would try them.
I am out of all three of these personally or I would have shared, I didn't even realise till I looked for you so I will be looking for them myself now.
I have Atlanta, Bella and Matador. If you want to check them on the web I can share if it is what you want.
XX Jeannine