I was given a 15-year old 114 x 118 GGL velux window that had been
sitting in someone's garage boxed for 15 years and have had it just
installed. The companion flashing kit outside says it is for Slates
but the insides clearly have Clay Tile type kits (U4 - it think it is
called in the old nomenclature whereas we need an L4 in the old
nomenclature).

I can pick up a brand new 114 x 118 flashing kit (EDL S06) today for
£35. But will it be compatible with the old Velux style window? No one
is quite sure...

Many thanks