hi ian....
my only thoughts on this is that using the word "clay" doesnt do your products justice......
it makes me think of dark sticky mucky clay, instead of the beautiful delicate works of art that your wife makes...sorry....
luna flowers describes what you sell.......flowers.........and by using a strapline like :
Beautiful and delicately hand sculptured .... would make me think, ooww i want to see more.......
im not saying that is a good strapline im just saying it as an example.....
maybe Think about what potential customers might be searching for.......then incorporate the words into your strapline....
i might be on my own with this thought and checking out the best keywords to use for search purposes might help you...