I had this issue on my Escort. What it took for me was to get the wheels balanced again....but this time using a seriously accurate wheel balancer. Non of the "I'll balance them for a tenner mate" kind of garages and even the big guns couldn't balance them so I used our super special one at work that we use for vibration assessment.

In discussing with a mate from our wheels and tyre dept. us "boy racers" (hes and old chap) are playing with the geometry to much. adding spacers, changing profiles of tyres and lowering the car upsets them.

Another area is that hubs can play a part to. It appears as wheel wobble but its actally the warped hubs effect on wheel rotation. Luckily for me i was ok, but its a good check. Get our you DTI gauge and just check if there is any run out/float/distortion.

Best of luck as I know how frustrating it can be.