My research into this section of the Oxford canal has uncovered tales of narrowboats and mules. I discovered the last narrowboat carrying coal in Great Britain was drawn by a mule called Dolly on the Oxford canal. (I have so far been unable to find an image of her…..).
A boatman was only as good as his horse and the sure footed, hardy and patient mule was able to pull 50 times as much weight in a boat than in a cart on a road. Mules were considered to be ‘standing tight’ when they stood still, spread all four legs and pulled until the boat began to move. (www.canalrivertrust.org; www.canaljunction.com).
meeting in the middle 
On our recent visit to Marrakech, there were plenty of working mules still in evidence, pulling small carts piled high with building waste and rubbish, I felt instantly sorry for them all; I’m sure Dolly was well looked after, and appreciated – because as you say, the boatman was so heavily reliant on a the mule. I wonder if this is where the saying ‘patient as a mule’ originated from? – it only just resonated as I read your post. Another wonderful image though.
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