jonmorris ) gurgled happily, sounding much like they
were saying :

Doesn't anyone here ever go in a supermarket? A six pack of 500ml
mineral waters costs about £2 (supermarket own brand). Buying in bulk
reduces the price.

Yes, but I am trying to avoid carrying a bag with me so I don't really
want to take two bottles in (one for the journey in, one for coming
back) because I've stocked up at home.

Isn't there a supermarket (even a Metro/Extra corner-shop-with-pretensions)
near work? Keep a stock in your desk drawer?