No I don't suffer with a vibration in 6th towing, although don't often sit at 60.
I tow a twin axle so much more stable but I normally drop from 6th to 5th going down hill to ensure stability and it allows 6th gear too cool off.
I think Druand had the dreaded vibration. Worth searching his posts Jaguar x-type sport gone
Jaguar x-type 2.2d sport one of my best cars ever sadly gone
Freelander 2 GS auto 2008 most unreliable ever ! gladly gone
Freelander 2 GS manual 2013 only time will tell !

Hi All
We've just changed caravans and weight of van has gone up to 1400kgs and Freelander is not happy in 6th unless we go up to 65mph. I have the same when towing load lugger 4 axle trailers. Fuel consumption in 6th is higher than towing in 5th. its on ly 4-5mpg. But engine does sound happier in 5th