Thanks to everyone for the suggestions about the name. For what it's worth, I checked on Ebay and found 22 entries for garniture set (although most of them seemed to involve candlesticks), 9 entries for console set (all involving vases) and, sadly, none for chest set. So garniture set wins the popular vote, but console set seems to fit my vase better. So I'll give it a go on Ebay sometime and see how i get on.
Thanks, Iain