It's taken me until now, less than two hours before the deadline, to come up with something that (hopefully!) fits. The base card is one of the BIG 8" squares from Craftwork Cards. The bird is the Penny Black stamp, the tree and blossom are Elusive Images from Graphicus. The flowers are punched from pearlescent paper and overstamped with the polka dots. They have glitter glue centres. The die cut butterfly is also from Craftwork Cards (ie. not cut by me!) and the quote on the left was printed on to acetate via my computer.
The finished card turned out nothing like I had envisaged it to begin with, and it's unlike anything I've done before, but then I guess that's what a challenge is all about!