Hi I am having the same problem and have looked at a few things. I have a sub floor which means trhat the floor I walk on is apprx 3 feet above the level of the water that is coming in. A tanking system will not work as the water pressure from outside will push the "tank" off the walls/floor it has been adheared to and allow the water back into the I am having to raise the sub floor by putting 12' of stones then adding 6/12' of waterproof concrete ontop of the stones. Waterproof concrete is approx 1/3 more expensive than ordinary concrete but it will avoid the need for a damp proof membrain that could rip or puncture on the stones and make ordinary concrete damp and allow water to penitrate. I saw the waterproof concrete used on "Grand Designs" where a family built a basement with a floor level 2 METERS UNDER THE WATER TABLE LEVEL!!!!!!!!! Hope this helps.