I'm not familiar with the sentencing guidelines for GBH and / or dangerous driving, and the sentence may well have been at the top end.
The question become, therefore, was the charge appropriate, and should the pustulant fucksack have been charged with a greater offence, such as attempted murder.
Pointing a 10 tonne speeding steel machine at someone strikes me as a deliberate act, and you have to expect that doing this is likely to kill, or maim at the very least.
http://webarchive.nationalarchives.gov.uk/+/http://www.sentencingcouncil.org.uk/docs/Assault_and_other_offences_against_the_person_accessible.pdf
The sentence is in line with the guidelines for a GBH conviction. GBH with intent would have been more like 5 years.