They can go outside in a sheltered spot but I would put them out in the day and back in at night for at least a week before leaving them out all the time. If the soil isn't frozen then you could then plant them where you want them to flower after they have been hardened off.

Many thanks both!

Be a bit cold in Llangollen this next few days though!

I agree move them inside at night. When your night time temperatures remain above 10°C, then you can keep them outside.

Thanks everyone. In that case, I’ll leave them in the potting shed, as it’s space I am seeking, and I would have to keep a space to put bring them back in each evening.

You could just fleece them outside? Most digitalis are totally hardy.