Dillwyn made the inspection, observing that 90% of the porcelain was ruined in the firing, but was so impressed with the quality of the surviving pieces that he invited Billingsley and Walker to use his facilities at the Cambrian Pottery to improve their recipe and process. An annexe was built for porcelain production at the Cambrian Pottery, where Walker and Billingsley were based from late 1814. The recipe was modified and improved, but was still wasteful enough for Dillwyn to abandon the project in 1817, when the pair returned to Nantgarw. Royal Worcester's attempts to sue Dillwyn, Billingsley & Walker for breach of contract was a further reason for Dillwyn to cease porcelain production at the Cambrian Pottery. The contract signed at Royal Worcester prevented the recipe being disclosed to a third party, which superficially, "Flight, Barr & Barr" could not prove. However, when Dilwyn's notebooks were interred at the V&A Museum, South Kensington, London in 1920; Bilingsley's recipe was found, but had never used in Billingsley's absence.