Sale of goods act is only between retailer and original purchaser.
Warranty is an additional contract between manufacturer and original purchaser
Neither are normally transferable to a second owner.
However, you may have some luck with direct negotiations with Scott in the event of a problem, but I wouldnt count on it at all. Some, like On-One used to do crash replacement discounts on even s/h frames as a gesture of goodwill.
You may also want to agree with the original purchaser that you can get back in touch with them to have them puruse a warranty claim if the frame fails during an agreed period up to the original warranty period, but that puts a bit of onus on the seller that they may not want unless they are rellay trying to ease the deal.
Finally you could blag it too, but may come unstuck if they check credit card details for example.