Used car has developed a fault - Can I demand money back from the dealer?

Last week I bought a used (2008 model) Hyundai i10 from a dealer. Within days the car developed an engine fault. I took it to an independent garage and they said it was the spark plugs. The car has a full service history with no advisories. Can I demand some money back from the dealer?
Spark plugs are not necessarily replaced at a service and I doubt these were. But the dealer is still liable for any significant faults that could have been present or developing on the date of sale for six months from the date of sale. He is liable to replace the plugs, not the independent, but since it's such a small amount he will probably cough up anyway.
Answered by Honest John on

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