Newts normally hibernate in the winter.How come you have two? They are better off left in the wild.I have inadvertantly disturbed them in my garden in winter and they appear to be dead but in reality are just "shut down" wating for spring.
Dont jump to conclusions- these may not be wild newts- in fact they should not be as UK wild newts are very highly protected and should not be removed from the wild. I would suspect that these will be imported varieties which can be imported and kept as pets. Can you let us know what sort you have?