Where did you get them from and who fitted them? If it was from a shop, you can just take them back and the shop are obliged to sort it out. Im not sure if you would be entitled to a refund, but if the goods are not in a fit condition, the shop would have to either repair or replaced.
There shouldnt be a problem if the place is reputable, but always remember you can start quoting from the Consumer Protection Act if you need to. Mentioning your local Trading Standards Office will also help in your favour in any discussion. Also, if they are being paid for on credit of any sort, then they are covered by the Consumer Credit Act
Look here:
http://www.tradingstandards.gov.uk/http://www.tradingstandards.gov.uk/
and from that site:
CONSUMER PROTECTION ACT 1987
Prohibits the supply of goods not in accordance with the general safety requirement or are unsafe.
CONSUMER CREDIT ACT 1974
Provides certain safeguards to consumers who purchase goods and services on credit.