The last CAA SCPL would have been issued in December 1989. The CAA then gave you 5 years to achieve the necessary hours for a UK ATPL.
The SCPL ceased to be valid in December 1994.
By that date you needed to apply for a UK ATPL or CPL.
So unless you kept a UK licence valid, I suspect you are in a spot of bother.
Head back in the books with Bristol...........
