With Nolan recuperating during the early months of 1985, the group returned to recording and released their next single in June. However, within the group, tensions had mounted to the point that Jay Aston no longer wanted to continue. After early promotion and a concert in Newcastle, she sensationally quit the group, despite still being under contract. Again, Bucks Fizz found themselves the subject of newspaper headlines, where it emerged that Aston had been having an affair with Andy Hill -- the husband of the group's creator Nichola Martin. Aston sold her story to the press in an article headlined; "The hateful, bitchy world of Bucks Fizz", while member Cheryl Baker was keen to point out that they were never friends. Aston was sued by management over breach of contract while a replacement member was quickly sought to continue promotion for the current single. Auditions were held at The Prince of Wales Theatre, where 800 girls were seen. Eventually, 21-year-old Shelley Preston was given the job and unveiled to the press and TV among much media attention.  In early 1986, the group's contract with RCA expired and a new one with Polydor was signed. The first single, "New Beginning (Mamba Seyra)" was released in May and brought the group back to prominence as it became a top 10 hit and one of their most successful singles. After two more less-successful singles and an album, the group took a break during 1987 and regrouped in 1988. After a successful UK tour, the group released their final chart hit, "Heart of Stone" (later a worldwide hit for Cher) and compilation album, The Story So Far. These proved to be the end for Bucks Fizz as a recording group and after a concert tour in 1989, Preston left the group at the end of the year.  With the focus on live work and touring, the group continued into the 1990s, now as a three-piece of Baker, G and Nolan. In 1991, celebrating 10 years together, Bucks Fizz released their last album, Live at Fairfield Halls. By this time, Baker had embarked on a separate and successful career as a television presenter and was eager to start a family. In December 1993, she left the group. Early the following year, keen to keep the group active, Bobby G (who was by then in effect taking over management of the act) and Nolan recruited two newcomers, Heidi Manton (who would later go on to marry G) and Amanda Swarzc. This line-up continued until 1996 when Nolan left and ex-Dollar star David Van Day joined.

Answer this question "Who quit the group?" by extracting the answer from the text above.
However, within the group, tensions had mounted to the point that Jay Aston no longer wanted to continue.