Well I ended up going for the Menja 130mm. Lovely fork with the nicest shock absorbing action I've come across.
In the end the choice came down to axil to crown lengths. The Menja was the shortest of the 130mm's at 498mm, giving me sharper handling for the same travel as the bike's original spec. A good compromise I think.
What a great bike it is too. That brutal, mechanical TARA monocoque still looks startlingly radical even in these days of sinuous top tubes and hydroformed pipes.