We actually managed to get through the next 70 ks of  varying depths of mud and water. A number of times John or I could see the full side of the van in our side mirrors as it seemed to take on a life of its own and take off into the bush backwards. Once we committed ourselves there seemed to be nowhere to get off the bloody road.
John did a great job but finally this happened. Fortunately the bit of verge was good to us while he repaired it.