Just an FYI, the Ohlins FKS218 cartridge kit for the Thruxton 1200 installs just fine and greatly improves the front end on the speed Twin. We installed this weekend.
Improves the front end in what way?
Replaces the the single cartridge non adjustable internals will dual cartridges that have fully adjustable preload, rebound and dampening that can be dialed in for your weight and riding style. The biggest improvements would be less dive under braking and just overall better handling.