Complex sentence: It was withdrawn from sale on the British market at the end of 1991, by which time Lancia sales were in steep decline, not helped by the recession, and just over two years later Lancia withdrew from Britain completely.
Split into simpler sentences: It was withdrawn from sale on the British market at the end of 1991, by which time Lancia sales were in steep decline, not helped by the recession. Just over two years later Lancia withdrew from Britain completely.