Not sure that is quite the picture. Various proposals to enlarge the 1-11 were put forward by BAC in the late 1960s being the Two-Eleven and Three Eleven which, like many other proposals for British airliners became mired in political wrangling.
In the mid 1970s an uprated Spey was proposed by Rolls Royce and BAC proposed the BAC 1-11 700 seating 134. Rolls failed to produce the uprated Spey and the project died. BAe was formed in 1977 and the 700 reappeared as a hush kitted Spey powered airframe to be built with the intention of re-engining with the proposed RB 432 from the mid 1980s. This project died when BA ordered the 737.
BAe then proposed the 1-11 800 powered by CFM56s. Seating 150 this became a victim of the A320/321 programme. By the time the Tay came into the picture the UK production had long ceased and Rombac were producing the 1-11 at a snail's pace. This stopped when the communist regime fell. It was four years before Rombac finished the last two aircraft. By this time BAe had no interest in the type other than any fees from the Romanian licences for each airframe produced. There were plans for Rombac to restart production of a new glass cockpit, Tay powered version and Associated Aerospace of the UK ordered 50 to lease to various airlines and Kiwi Airlines in the US ordered 11 with five options.
Associated Aerospace went into liquidation so their order died and with just 11 firm orders the Romanians lost heart and cancelled the project.
In the meantime, Dee Howard in the USA re-engined an extant airframe as a Tay demonstrator and it duly appeared at Farnborough in 1990 where some interest was shown but Dee Howard, the proprietor, was in the process of selling his company to Alenia who dropped the project, concentrating on the re-engining of UPS 727s with Tays.