How Can I Stop Shrews Coming In The House I Do Have A Cat Who May Be Bringing Them In Alive?

Unfortunately, there is no sure way to make a cat stop bringing in the shrews. When a cat does this, they are hunting for food, and because they look at you as part of the "family" so to speak, they bring it home for you to have.
Usually though, they do make sure it's dead before they bring them home. If you don't have any children, then I would suggest mouse traps, that are more sensitive and respond faster as shrews weigh less than mice.
Don't scold the cat for loving you enough to try to help feed you, it's just their nature. If the traps don't work, use the chemical based traps. Remember to make sure that they aren't out anywhere for the cats to step on and get hurt.
If these methods don't work, call an exterminator, maybe they can give you some pointers. Hope this helps, good luck.