Any hope?

Hi all! I’m new here but need some advice please.

I bought a De Dietrich free standing cooker (CDI499x) from biasco on 31/10/2006 which has since failed (hob and display). I believe that biasco has been taken over/gone bust yet I am told that any claim under the sale of goods act (Fit for purpose/ as described) should be made to the retailer.
De Dietrich are saying that 1) it is repairable, therefore it has not failed. 2) Their responsibility ended with the 12 month guarantee.

I paid £854 for a cooker made by people who (on their website) say ” Our appliances should give many years of excellent service” yet their customer service manager says ” we wish to provide an appliance that will last a customer a lifetime. However this is not always possible or realistic”.

The cost of repairs using a fixed price company suggested by De Dietrich is £156 and the manufacturer is not willing to contribute.

Any advice would be gratefully received.