HMV are selling MS Points for £9.99. I am 99% certain that these are 2,100 points cards, since apart from the special edition ones, like the Lost and Damned ones, that is the smallest size they come in. And they are reduced from £17.99, the rrp for 2,100 points.
MS Points - £9.99
They are in stock, and ready for shipping in 24 hours. Also, if you've been to McDonalds recently and got some of the HMV vouchers from there, they can also be used online for this purchase.
UPDATE 8:30PM: Looks like these were a misprice, as they are now adding to the cart at £17.99. Hope you got in there while you could if you wanted some, and here's hoping they'll honour it.
Xbox 360 Accessory - Official Microsoft Points Card - Completely shipped. Shipped Date - 20/04/2009 £9.99x3. £29.97
Looks like they are honouring at least some of them. Let us know if you get them too.