This is probably the best price available that I can find. Not a bad deal if you use this stuff. You can mix the flavours at the checkout screen, just leave a note in the additional instructions box. I spoke to the guy on the phone and he said the offer is until the end of the month even though the website states it's a weekly offer. Delivery is free (3-4 days) else you can opt to pay for quicker delivery times. Sent to your door via Parcel Force and requires signature.
Hope this helps someone :)