Question Author
Good idea, Tilly, but it might not be quite right in this particular case!
Actually, I've now ordered some flowers from Ocado. This only works if the delivery is going to your own address (or maybe there is a way to send an Ocado delivery to someone else), and if you add something to bring the order up the minimum spend (£40). In my case that was easily done with some wine. Delivery between 7 and 8 for £1.99, job done.
You're probably wondering why I don't just go and get the flowers myself if it's going to my own address, but nothing quite beats the drama of a Valentine's Day flower delivery - even if it is just the Ocado driver!