maybe finish balancing will do the trick?

that's balancing with your wheels on,

than you can prevent unbalance in your brakediscs etc
 
maybe the wheel u put on the front from the rear was buckled but u couldnt feel it as it was on back???

try put it on the rear again and go a spin
 
Check the tyres mate as i had a simular problem, turns out my rear drivers side was completey **** and out of shape..which causes massive shaking over 80ish
 
I had a brand new tyre put onto the rear same side so i have put that onto the front,

I have looked at my tyre today and the tyre is on the wrong way round, It says "inner side" on the side of the trye that is facing the outside, Just going to have to get it swapped around as i cant take it back to the garage that fitted it as that was in bradford about 130 mile away,
Hope this sorts it out