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If you don't have a resistor then you will have the earlier type fan. This is identified by the fact it has four wires entering the motor. Sometimes these can be re brushed at a very low cost but sometimes the motor is beyond repair. Have a look on here for re brushing three speed fans.
If you decide to replace the fan then the two speed fan with a resistor is plug and play providing you replace a petrol set up with a petrol set up and a diesel set up with a diesel set up and there are various aftermarket options.
One thing to note is that although petrol and diesel motors are the same the relay boxes are totally different and not interchangeable.

The only other variant is some 1.8 petrol models are fitted with a three wire two speed fan, these suffer the same problems as the four wire fan with the brush failure. (As yours is a KV6 it should not apply)