Damage looks relatively minor - Thinking how the three wheeler might be more prone to aquaplane than a four wheeler. Could it be that the vee of water jetted from under the two front wheels coincides with the rear wheel at a certain speed?
What make were the front tyres? Look like Blockleys. As soon as the load goes off the rear, that tyre is mostly just keeping the keel of the ground, so I would look at the fronts for blame.
