I keep reading this 70,000 miles number and at first it worried me - i was way past that with my original 2003 VCU that's been there from the factory. Now i just don't think about it - i'm on 130,000 miles and all i do is make sure to occasionaly check the tipex lines are moving and take it out on a snowy / muddy field. So far no problems.
You pay your money (or not) you take you're chances. As this is a known fault I preferred not to take the risk so renewed mine not long after purchase at 103,000 miles, £250 seemed a reasonable price to pay for piece of mind, mind you I still remain a Green Flag customer just in case something else major drops off