Hi Tina. I've got no personal experience with heathers but I'm just about to purchase some summer flowering ones. Not sure if this is any help, but this is what I'll be following when I receive the plants - J Parkers website says:-
They thrive in sunny, well drained positions in lime free soil, though they will also do well in partial shaded areas. Plant 30-45cm apart to give ground cover within three year s. Cultural Instructions Use plenty of peat when planting and plant deep with the flower foliage firmly on the soil. In the first season after planting do not allow the plants to dry out. Also avoid fertilising as this could be damaging, though once established the plants will react to natural fertiliser well, such as manure or hoof and horn.