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.