I just wanted to share a success story, that many of you have probably found out anyway.

I recently bought a multipla and purchased the factory-fit roof bars for it. To my horror, the roof bars are too deep for the clamps for roof boxes designed for the Thule/ Halfords/ Paddy Hopkirk square section roof bars.

Having spoken to Thule and taken the Multipla bars to Halfords I have found the solution!

If you by a t-track adapter kit (around £10) thule part number 697, these will fit inside the roof bar (where the rubber strip goes), and you can then use these to attach the roof box rigidly to the bars, without extra clamps etc. It turns out to look visually neat, and strong at the same time.
Once you know the position laterally of the bolts, you can cut the rubber strip to fit around the mountings!

Not surprisingly, Fiat themselves were SINGULARLY ignorant and unhelpful (both the parts departments at dealers and Fiat UK telephone line).

It is difficult to take Fiat seriously sometimes!

If you have purchased a brand new Thule box, suitable for aero bars, the clasp fitting may stretch to the width of the Multipla bars, but I can not be sure.

Happy motoring!

John

I made my own. Looked pretty crappy though - just like most of my DIY efforts.

I made my own with 60mm exhaust clamps covered with some rubber hose (from a Mk 1 Triumph Stag heater) and I have to say they look smart and work very well. The only downer is that they do stick up into the box by about 50mm.
Regards Neil