When originally installed, the glideslope at LCA and Plymouth were commisioned at 7.5 degrees, the DHC Dash 6 was the only type certified to operate this angle of approach. But with production of this aircraft ceased trials were done to certify other a/c types to operate at 5.5 degrees. I'm not sure when the changeover took place but LCA operated at 7.5 deg for quite a few years from its opening date in the late 80's.