Cold vibration

Hi, how you all doing?

Got an annoying vibration in my 55 plate 2.0 tdci 130. It only seems to happen when the car is cold and I am doing motorway speed (70-80mph). It feels like it is coming from the rear of the car i.e. through the seat and floor, not through the steering wheel but strangely seems to have got worse since I put Goodyear Eagle NCT 5 tyres on the front.

[color:red]Admin Edit. [/color]
Your comment (and any below it) regarding driving beyond the national speed limit on the public highway contravene's forum rules.
It also - and more importantly - highlights on a forum section which is viewable to members and non-members alike (some who may be police or other such law enforcement) that the speed limit has been exceeded. Such activities are not condoned by fordmondeo.org, nor do we take any related responsibility thereof
Any ideas?