In March of this year I purchased a one owner Mondeo Ghia V6 Auto with 22500 miles on the clock from a local Ford main dealer plus a "Ford Protect" extended 2 year warranty. I became concerned at the lack of power when climbing hills and returned the vehicle to the dealer for check in June. I was informed that no problem could be found. The performance has since worsened and upon returning the car again on 28 July I was subsequently advised that all 3 catalytic converters are blocked and that the repairs are not covered by the warranty. The bill for repairs, including labour, will be about £1700 but the dealer has offered to reduce this by 50%. I appreciate the offer but had thought that any faults found within 6 months should be fixed free of charge. The dealer says that they will only do this within the first 3 months. Should I accept the 50% offer or argue for more and if so on what basis?