Oh Smurfy you should have tasted the old Milk Tray selection! There was one called Lime Barrel which was thick chocolate with a lime crodial filling. It was divine. I can't think why they got rid of them (about 1975 I think).
A few years back - Thorntons did a white chocolate Lime Truffle. It was wonderful. Creamy but sharp and just the right amount of sweetness.
Chocolate Limes - those horrible green sweets with lime candy and chocolate paste stuff inside just don't do the chocolate/lime combination justice.