Williams did a very nice job on covering mine to match the tan hide. The work was carried out prior to me owning the car so I'm not sure on the cost. Certainly looks very nice and not at all like an add-on.
You've also got the Wiiliams Motolita boss as well, which sits closer to column shroud and hides the nasty gap!
Neil.....I might have a spare shroud off my Roadster lurking somewhere in the garage if you want one to play about with.