When Rolls Royce was privatised in 1987 how many shares were allocated to each subsciber given that I believe the share offer was oversubscibed 9.4 times.

Does anyone know how I can find out if a member of my family ( recently deceased ) had shares in RR as I can find no share certificate but evidence that they did apply for shares at original flotation. Do not want to spend a small fortune on asking a commercial company to find out as it may come to nothing.