Not being one to waste 1/2hr of typing, I'll leave this post here even after reading the one above - CRAP
I'm in (4) forums, the common denominator for death wobble is swivel preload
I've not experienced it, but after I rebuilt my steering (all) I had wandering & skittishness over bumps
It turned out I had too much toe out (required). After 5mins & 1/4 turn on toe rod, my steering is perfect - Your Rover dealer didn't align properly in my opinion
Take what Joey says to the bank, if your swivel preload is bad, you might feel play by jacking up the front, grabbing the tire top & bottom & shaking the shat out of it.
If you feel play, certainly it's swivels although you might not feel it, those wheels are HEAVY
luck,greg