I plugged a Sony PS 2 into the TV but it would not work so I tried to tune the TV to get the PS signal, in doing so I have managed to stop the TV receiving the satellite signal even though I never touched the TV AV butoon, how do I retune it

You can re-tune the satellite receiver output frequency also. There should be a trim facility to change the frequency to your TV's new receiving frequency. Check the operation manual. Often there is a note at the rear panel of the sat receiver with a tiny adjustment screw. Or change one of the empty TV channel frequencies to that of the sat receiver.

Success !

Stop, do not re-tune any thing.

Do you have more than one connection points do you have on your TV?

Leave the satellite connection alone. Place the PS2 to an empty connection on your TV. There is usually one on the front of the TV. Power the Satellite off and on to reset it. Also power the TV off and then on to re-set it.

If you want to use the PS2, use the "INPUT" selector to find the port where the PS2 is connected and play-away to your heart's content.

See where the cable(s) go from the Sat out to the TV, May be Coax and be Ch 3 or 4.
I agree with not tuning anything, More likely a button pushed or a Menu setting.
How did you Tune your Sat Receiver?