Well I wouldn't - if it was March, it might be worth it, but doing it now would mean doing it whenever its cold right through till Spring. The plant is budding because it's been mild, but it's way too early - happens sometimes, I'd leave it to take its chances. Some apple trees had flowers before Christmas around the country...

Thanks, Bamboo - you've answered the same question for me, too! I didn't really fancy trekking up the garden with miles of fleece to wrap 16 trees every time the temperature starts to drop. Quite a relief, really.