MK2s use same radiator as the equivilant engine MK1

if its a 1.8 use 1.8 8v mk2, if 1.5/1.6 use 1.6 MK2 rad.
if its 1.0-1.3, erm, think you need a 1.3 MK2 rad, not 100% sure
edit: oops, forgot earlier MK1 1.5-6 and 1.0-1.3 had a topfill rad:
From GSF:
17323 - RADIATOR-430mm MK2 1.3 - 31.50
17333 - RADIATOR-430mm MK2 1.6 - 38.50
17332 - RADIATOR-525mm MK2 1.8 8v - 46.30
17322 - RADIATOR-430mm MK1 1.0-1.3 (top fill) - 54.00
17331 - RADIATOR-430mm MK1 1.5 & 1.6 (early top fill) - 67.50
17333 - RADIATOR-430mm MK1 1.5 & 1.6 (late) - 38.50
17332 - RADIATOR-525mm MK1 1.8 8v - 46.30