The wires switches were all black, they are quite old. There's no obvious earth wire and no loose wires hanging around either.
As has been said, no house would have been re-wired in the past 30 or 40 years without an earth on the lighting circuit. Someone is either lying, or has been conned.
Whatever, as I think you know, if there is no earth available, it is contrary to regulations to have metal switches (the greatest danger) or metal light fittings. You probably need to take this up with your landlord but, before you do, perhaps you should consider whether your tenancy agreement allows you to go around changing light switches!
Kind Regards, John