@AllysonShaw @bearsong I second potatoes. We had great success with the Mayan Gold heritage variety, which was the first potato to be grown on these isles from the indigenous Phureja potatoes of Peru.
Forget your Maris Pipers, these make the best roasties and thick-cut chips (or fries, for Americans reading!) of any variety! Hands down. Some of the top restaurants are now recognizing this and using this variety exclusively.
If you have clay-laden soil you may want to enrich it with compost.