Outer Limits 4x4 Board

A friend at work (05 TJ) has just had this kit installed by a reputable Jeep workshop and it is leaking fluid from where the speedo goes into the extension housing. It has been back to the workshop and they have changed the seal 4 times, but when he got it back to work yesterday, it's still leaking the same.

Needless to say he's getting very annoyed with the fact that he spent a ship load getting it installed and having a simple problem that seems to be too hard to fix. The leak is minor, but a leak none the less.

Has anyone had this problem before?

There's a cheapo o-ring seal that fits around the speedo asembly.
if it's been replace multple times and still leaks there must be a problem with the tailhousing.