Sadly that's completely the wrong spot - what you need to avoid is early morning sun! The reason is that when there is a frost the flowers need to thaw out very slowly. When the sun gets on too early they thaw too fast and it damages the petals which then go brown. You need a peaty acid soil and as they are in pots you can plant them now as long as you keep them watered. If youyr soil is not acid dig out an area considerably larger than the rootball and fill it with ericaceous compost.

Yup totally agree morning sun is the wrong spot. Sun from late morning onwards is fine.