Ok so here is the verdict!

Changed the fluid with genuine ZF Lifeguard 6 and the lurch is GONE!

So all those out there who want to give it a go I suggest it - Don't be a tightarse and try and put some other fluid in it cause you will most likely screw your transmission. ZF Lifeguard 6 for the 6 speed and Lifeguard 5 for the 5 speed.

If when you pull the plug and inspect the fluid and it is severely burnt and you see metal shades in the fluid put the plug back in because your too late and the tranny is toast!

The "Lifetime fluid" rant from BMW is CRAP! Even the engineer from ZF said that they recommend replacing the fluid at 100K as that is deemed "Lifetime" and earlier if the vehicle has towed anything in its life.

GOOD LUCK