I found a good solution for me:
A large plastic mixing trug (bucket) from Wickes. I coil the hose down into it, it easily fits. The hose nicely stacks on top of it's own coils. I have space left in the middle for (stacked) buckets. I put the rest of my damp/wet gear in the buckets.
There's no drips on the customers floor, or my van. And, it's all easily transported between van and house.