The Ford warranty is one year manufacturer followed by two years dealer. However, what you have been told is unacceptable, so, providing you are dealing with the same dealer who supplied the car, you can demand that it is repaired. However, first yo need to check that the leak is not your fault.

Lift the bonnet and make sure that the drains from the bulkhead vent well are not blocked, leaving rainwater nowhere to go except into the car. Check that you have not done something with carpeting that interfered with the door seals. Check the door bottoms and use a wooden stick to make sure that the door bottom drain holes are not blocked. If you need law, it's here: www.honestjohn.co.uk/faq/consumer-rights/