Head office phone number 0845 3021234. But they're as useful as a chocolate teapot. I've had a huge moan at them today. Ordered 2 dresses last week, were due yesterday, didn't appear so I rang today only to be told they're out of stock and won't be getting anymore. And no one thought to contact me!!!! Yet the ruddy dress is still online as available. M&S are a pile of pants!!!!!
Had a friend who worked at their Head Office who was shocked by their attitude to customers - emails via their website would sit on people's desk for weeks, and then get shunted to someone else to reply, for instance. No appreciation of customers or understanding of their needs at all.
So no practical help, but sympathy.