Guarantees are useful but they do come with limits

QI PAID £11,400 to a local dealer for a new Lunar Venus caravan in July 2013. I have not used it much. I recently noticed that the front window, consisting of a double layer of plastic, has a band of visible abrasion where the two layers have flexed and rubbed together.

I took the caravan back to the dealer, who took up the problem with Lunar Caravans to try for a free replacement. But Lunar says the window guarantee only lasts two years – the dealer quoted £436 for fitting and supplying a replacement.

I feel a window should last much longer – especially as we have only had a few trips and the problem seems to have been caused when the caravan is travelling behind the car. I am concerned that if I pay this money, the same defect will occur again after a few years. Alan B

AGUARANTEES are good but come with two significant related drawbacks. They end suddenly – a defect one day is fine and the next equals a big bill – although EU legislation

Your caravan was covered for three years for most things but only two for the windows. It is one of Lunar’s lighter models, designed so you don’t need a big car to pull it.

Lunar says the defect might not be use-related and it has found similar defects in one or two other caravans. The construction is designed to flex to absorb movement in some of the body panels. It believes it would be very unlikely for the same problem to reoccur.

However, it is good that you did not take the first “no” as the end of the matter.

Lunar has now seen a photo of the problem and while it sticks by its two-year guarantee, it is offering a compromise to meet you half-way. It will supply a new window to your dealer free of charge as a gesture of goodwill.

Lunar estimates that a caravan specialist will take 90 minutes to replace the window but you will have to pay for that.

But the free replacement should reduce your overall bill to under £150 including VAT.

has helped avoid this “cliffedge” on electrical goods. And time limits apply however much you use it – your defect might have appeared earlier if you had used it more often.