Not sure if we've already discussed this, but was in Waitrose today with money off shopping vouchers (£9 of £90, thank you very much! :o )and found that you can't have alcohol as part of your shop if you want to use a money off voucher.
I wasn't buying any anyway, but there was a note on the door as you go in and then the checkout staff member also checked with me before she put the shopping through.
It is a little bit of a pain as it's normally my go to if my shopping isn't getting close to the spend for the voucher, usually I can lob in a bottle of something to take up the value without having to trawl for lots of smaller items.