Thanks everyone for all the suggestions. After much tearing out of hair it seems like it is the tailgate lock vibrating against the catch bar (I can't think what else to call it) when driving along. When the tailgate is closed there is no obvious movement when I push firmly against the tailgate and it needs a bit of effort, almost a slam, to properly shut. I've tried adjusting the stops one notch which helped a bit but made the tailgate even harder to close (and still didn't stop the rattle entirely). Wrapping the catch bar in a couple of turns of electrical tape has stopped the rattle completely so it's something to go on my (very short) list to be looked at when the car goes in next month for MOT and second service.

 

I'm pretty sure the Yeti is the first car where the catch bar is metal contacting metal in the catch itself - on previous cars there has been a hard rubber sleeve to absorb any vibration. Or is mine missing something?

...I'm pretty sure the Yeti is the first car where the catch bar is metal contacting metal in the catch itself - on previous cars there has been a hard rubber sleeve to absorb any vibration. Or is mine missing something?

I've just checked - yes, metal-to-metal.  And I think you are MY13, like me?  (Most unlikely to have changed, anyway.)

A lot of rattles are temperature dependent and at this time of year a lot of parts have "shrunk" and will often rattle.

That's exactly what the doctor said to me the other day.   

 

Fred

:clap:

Good job it's starting to warm up now!