... the cables were wired incorrectly. ...
do you mean at the appliance, behind the sockets, or at the consumer unit?
I would be inclined to start at the beginning and look at the insulation colours at each point
otherwise there might be compensating errors
you may need to think about calling a professional to inspect and test.
If you have a multimeter you should expect about 240v between P and N and between P and E, and about nil to (say) 12v between N and E. This will depend on your installations earthing method. You should expect about 0v between E and your water pipes and gas pipes, and also the metal casings of all appliances such as cooker, fridge, washing machine, shower.
post some pics of all the cables around your meter, consumer unit, company fuse and incoming supply to give us an idea of what you've got.
you can get a plug-in tester with 3 or 4 neons to show incorrect connections, but they only identify very gross errors, and do not detect poor connections or crossed N and E.