Distance selling law ..Item damaged in transit.?

I recently sent back a pair for �70 speakers to an online shop using distance seling regulations. I Sent them back in the packing they arrived in. However i reciviced an e mail from the shop saying that they recived the item (signed for) and its been damaged in transit (the retail box not the speakers) and they/i will file a claim through the courier. However i only have �30 insurance on the speakers from the courier. Which i would accept however.. the shop signed for the item as checked.. there for they would have known/seen the box was heavily damaged. Doesnt the responsability fall upon the shop to give me a full refund as they have accepted the parcel and now changed their mind about the state it was in?