Another vote for Bloom & Wild.
Been using them for a while since my sister moved and apparently Interflora can't deliver to her new address.
Not always as reliable as the likes of Interflora, as they use the likes of royal mail for delivery, so you can't guarantee delivery on a specific day (unless you pay the higher rate postageby courier, which I'm too cheap for), but I find it works just fine for me, as long as the birthday flowers arrive before the birthday not after, all good

There's usually a discount code available as well, always a bonus, and they use letterbox friendly boxes, so don't need someone home for the delivery.