All we have from Tesco so far is this comment on facebook from a few weeks ago:
Emma Reynolds is in the PR department: firstname.lastname@example.org
tel: 0800 505 555
in the past companies that have been at the receiving end of protests who have had freepost addresses have been sent engine blocks, bricks, tyres etc. It costs them a lot of money.
TESCO SCO 5043
Dundee DD2 9XU