I have the 2 speed S-Type Titanium with 54 - 12 + 16 cogs so 55.9 & 74.5 gear inches.
I did get a modified sprocket from Steve Parry soon after buying the bike.... but to be honest I just couldn't bring myself to grind a section out of my beautiful Titanium rear triangle I would like a like a Schlumpf speed drive but I'm just not sure I would like to add weight to my Lightweight Brompton