Many thanks for the info so far.

There appears to be 3 sets of winglets in existence...
Masak,
Schempp,
Maughmer.

How do the Schempp Factory winglets relate to Masak
winglets from the early '90s, are the figures of 55%
& 20% from David Collings work likely to apply to the
Schempp winglets?

M&H sell Maughmer winglets, but they're also the agents
for Schempp Hirth. Are their winglets for the original
Discus from the Schempp factory (Fat & Draggy) or are
they Maughmer design (Newer, thinner etc. etc)? This
second question is purely academic as I've already
got a set of factory winglets & am not in the market
for more, but if anyone here knows the answer I'd still
be interested

Thanks