Well they did used to sing “ we’re Man Utd we do what we want”There was also a limit on the amount of foreign players that could play around that time and English clubs would bleat that Scottish /Irish were deemed foreign under UEFA regs which caused some discussion of merging the SFA, WFA & NI FA with England and doing away with separate national teams to help teams in Europe.
Bottom line is that they may have had 5 locals but without checking I'd guess the usual starting line up for domestic games had less than that.