Just an observation, Torres Sangre de Toro is 12 euros on The Bistro wine list, are we talking about the same restaurant here? I notice you call it 'Le Bistro', which sounds a bit French to me and the restaurant next door is the Le Bistro D'Alain.
Mark-up on wine is something that bugs me too but then restaurants do have to make a living. Not being anything like an expert on wine, I always buy the 'house', which in The Bistro is 9 euros a bottle and very drinkable, this seems a very reasonable price to me. We recently had a meal in The Bistro, 2 starters, 2 mains from the new 7 euro menu and 2 puddings with a bottle of house white, total 45 euros. This was for a very good quality meal in an excellent restaurant and would have cost 50% more for the equivalent in the UK.