 
 <translate> The relevant sentence in the passage is: In 1987 it became an independent company with 33 staff as a result of a management buy-out, led by Rod Aldridge, and was first listed on the London Stock Exchange in 1991.
So, the answer is 1991. <ibo> Ahịrịokwu dị mkpa na amaokwu ahụ bụ: N'afọ 1987, ọ ghọrọ ụlọ ọrụ nwere onwe ya nwere ndị ọrụ iri atọ na atọ n'ihi nzụta njikwa, nke Rod Aldridge duziri, ma debanye aha ya na London Stock Exchange na 1991. Ya mere, azịza ya bụ 1991. 