My oil light keeps flashing on my seat leon fr 1.8 20 v turbo i've checked the oil and its ok any ideas?

I am not sure about that model but most Leons have an 'Electro-mechanical' system, Basically it's an electric motor powering the steering so there is no oil.

Seat Leon >> Lights. - Turn the light switch to position 0. in the light switch lights up.
http://www.seatia.com/secon-545.html
- Turn the ignition switch in the key-operated switch in the glove box to the position ON fig. 25. The driver is responsible for the proper position of the key-operated switch. You should deactivate the front passenger airbag only if you have to use a rear-facing child seat in exceptional cases.
http://www.seatia.com/secon-465.html

Do a compression test. Your engine may need an overhaul.

disconnect negative battery cable for about 15 min & reconnect

U HAVE ACTIVATED SPEED WARNING!!USE MANUAL TO DEACTIVATE!!

Have a look at the sensor. If it is OK then you may have a blocked oil passage in the engine. This is a bad situation.

You did not say what manufacturer or vehicle model this pertains to.

Before you run aengine anymore remove the oil light switch and check it with a gauge in the oil light switch is faulty ,what engine is this a diesel or a petrol

piston rings may be worn. do a compression test

my seat leon seems to burning oil im having to put oil in regular had a new turbo fitted any other suggestions please

replace the oil sensor and it should stop