Nuts are good - almonds are the lowest in carbs but I would avoid raisins as, like all dried fruit, they are high in sugar. You could try olives, BabyBel or other cheeses, mini chorizo bites (they sell these in snack packs in Waitrose), chicken satay sticks, prawns with a mayo dip. If you are up for a bit of baking I can point you in the direction of lots of savoury muffins good for lunch ideas. Also if you like kale you could make your own kale crisps - plenty of recipes online. For drinks, if you don't like water (I'm not keen) buy a bottle of Robinsons Squashed and carry a reusable water bottle with you. It's a really small bottle and you can just squirt it into water which you can get for free anywhere you may be stopping.
http://marmaladeandmileposts.com/archives/22650 These are good for spreading with pate or cream cheese
http://divaliciousrecipes.com/2013/08/27/flatbread-coconut-flour-and-psyllium/ These could be used like a pitta or wrap