Engine turns over but won't fire up on seat ibiza 2.0 16v have changed distributor cap and rotor arm as advised by rac, have fitted new starter motor and still no luck. after pulling out spark plug leads there is excessive oil in plugs 2 and 3. any ideas?

Are the wires still in the actual distributor cap? If they are simply swap them over ONE AT A TIME! The firing order is the standard 1-3-4-2, Number 1 cylinder is the one nearest the engine belts and pullys. First take a careful look at the actual distributor cap. Some manufacturers mark the position of the number One terminal on the cap.
The issue you may have if there are no wires fitted is the distributor's direction of rotation. Some manufacturers use a clockwise rotation and others use an Anti-clockwise rotation.
A method to figure out both is to turn the engine clockwise By Hand through 2 to 3 full turns to line up the timing marks to Top Dead Centre. I've done this with the cap removed to see which way the rotor arm spins. This should line the rotor arm up to terminal One for cylinder One.

on the four stroke right hand ( clockwise ) turning engine the firing order is 1-3-4-2 but there are some exceptions on European model. The firing order is also clockwise set because your engine is right hand turn. For you if you like to see also what I stated you can remove the distributor cap if you know how,and by starting the engine you will see the rotor arm turning clockwise.

turn the key but not all the way and have some one turn the Distributor slowly.is your batteri fresh also check your starter.

You need to have the ignition control module checked (It's inside the distributor)

Sounds like timming to me?

Try yhe battery

you said you repl dist cap that means you don't have a crank sensor you have electronic ing module. remove your elec ing module have it tested most auto parts stores could test your module, or check your coil at the neg terminal. should have power. if not you lost your primary volt from your batt.your secondary power is coming from your electronic ing module from the module to the pos terminal on the coil, when the eng cranks,from the coil to the dist cap , from the dist cap center to the rotor then out to the plugs,this all happen pervided the timing belt or timing chain is ok. the cumbustion chainber needs 3 things , thats fuel, air, and spark.

without looking at it i can only guess. Sounds like you need a new distributor cap and rotor arm. Hope this helps...

Yes continious cranking of an engine puts a big strain on a starter in any weather, but almost certainly in cold, it takes a lot of amps to turn an engine, It maybe the fuel is starting to freeze?, Maybe it's an electrical issue such as points, plugs timing, distributor cap, rotor arm inside the cap, maybe it's just settings

to be honest with you, stop throwing parts at this car and have it diagnosed properly by a good technician.