Expert witnesses or not, believe me a jury will normally make up its mind AS THE CHARGES ARE READ. Now I know that takes a lot of believing but it is true. Some of the reasons are these.
1) They think: well the police/CPS wouldn't bring it to court if 'they' didn't think the accused was guilty.
2) The police/CPS are much more experienced than we are.
3) The accused ran off after the event, which tends to indicate guilt.
4) The accused did nothing to render any assistance to the injured party.
5) The accused didn't inform the police that they had done damage to the guy on the deck or stay to justify why they acted as they did.
6) As No5, but didn't phone for an ambulance for the injured party.
7) We are told that all these so called indicators took place, but there is no proof of such things happening on the video evidence, or in witness statements or testimony.
8) The arresting officers had to establish the accused's identity and then find their place of abode, further indicating guilt.
9) In the face of all these questions raised the accused denied the charges.
10) The accused's 'body language' in the dock seems to be highly suspect.
Juries are not alone in the manner they form conclusions. Can you remember the last time you went for a job interview? Well the person interviewing you made up their mind about you within the first ten/fifteen seconds of you walking into the room. The rest of the interview (how ever long it took) was spent with the interviewer looking for reinforcement of their initial impression. It wasn't spent with them looking for reasons for them to change their minds.