www.growsonyou.com/.../11613-meconopsis-betonicifolia-himalayan-poppy has some details form members given last year.
Ive had a look in my RHS Propagating Plants book and all it says is '...pot of plant out seedlings in ericaceous compost or lime free soil.'
Not that much help. This is for spring sown seedlings.

Thank you for your reply, and I did sow them in June.
Bought the seeds from a garden/garden centre at a place called Plant World, near Paington. They were in flower and were beautiful, I only hope they will grow in Sheffield.

they stand a better chance the further north you go, the best blue poppies I'v seen were in Scotland.

Thanks Bizzybee
I had heard that they grew well in Scotland, but the garden centre in Devon was on the side of a hill, you could for miles when in the cafe. Perhaps the height was the main reason they grew so well there.
I have potted them up today in ericaceous compost, so perhaps they will survive in my cold greenhouse.
Pauline