Miranda,
Usually dealers need to make sure that a car has been properly serviced before selling it. This includes all the safety measures that they need to take to ensure the car can be driven safely. Some dealers will give you a warranty of 4 weeks while others may give you 3 months worth. It all depends on the dealers really, some may not give any warranty at all. You should check if you had any warranty at all on the car and if you were still covered by the warranty when the incident happened. If that's the case, then you can claim compensation for your loss.
Even if there was no warranty, you can still talk to the dealer and see if they are willing to compensate you. If they refuse, you may want to seek the advice of a professional person or speak to the Citenzen Advice Bureau to see if there's anything that you can do as this was clearly not your fault at all.
