I see your point. No point wasting time and effort if there is not a large chance of a conviction. I would have seen driving at the cyclist in an attempt to knock him off would be enough intent for me if not GBH the lesser one of which its name has left me. Naturally if you knock someone off their bike their is a huge chance of them getting hurt of which would have been considered at the time I would have thought and he chose to continue. Just my viewpoint.
A defence solicitor could have easily used this to negate the 'intent': "My client was driving a camper van at a cyclist. If he had truly intended to inflict harm, there is no doubt that he would have been able to do so. The very fact that he did not, and merely knocked the gentleman off his bike, stopping his vehicle before any further harm was caused, proves that there was no true intent to harm him. It was a moment of madness, and my client is an upstanding and respected.... and so on"
I can see why they didn't run it, because they don't like the prospect of losing - it affects their figures. That said, I would have thought it was worth a punt (as long as the other charge could be run concurrently) and see who the jury went with on the day.