Canapés are one of life’s delights and surprises – surprises because drinks party invitations usually give nothing away. Perhaps because ‘nibbles’ is such a hideous word, or perhaps just because of invitation convention, hosts tend simply to put ‘Drinks, 6.30 to 8.30’ on the Paperless Post card. So you arrive with no idea whether you’re in for two hours of fizz on an empty stomach, or for a culinary treat in a succession of miniatures.