“I just do not see where this guilty of section 20 has come from”
It comes from the jury believing that he had committed Grievous Bodily Harm without intent.
Actually his insisting on a trial has cost him more time inside than Eddie calculates.
Assuming he had pleaded guilty at the earliest opportunity (which in practice would have been as soon as the lesser charge was offered) he would have been entitled to a full third off his sentence, thus reducing it to 14 months. He would have been released automatically at the halfway point (no “good behaviour” necessary so I don’t know where that suggestion came from). This means he would be released after 7 months. “Home Detention Curfew” gives in 90 days (approximately three months) off of that meaning he should serve 4 months, which he has already served on remand. So he would have been “coming home” almost immediately.
As it is now he will need to serve 10.5 months with three months benefit from Home Detention Curfew. So 7.5 months, less the 4 months spent on remand means that by insisting on a trial, against legal advice, has cost him 3.5 months inside.