Errmm, i could be wrong but...
Simon could be guilty of murder. He killed Geoffrey. I think even though he is scared, this still satisfies the test for direct intention. I don't think it's recklessness, even though some could potentially argue this. I don't think it can be pleaded down to manslaughter.
Simon and Lazio, attempted theft/burglary that was planned? could or could not be a crime. Dishonestly, appropriating ,property,belonging to another, with the intention to permanently deprive the shop of the phones
. Some may say attempted robbery because they 'intended' to scare anyone who would cause problems. This could be construed as using force to affect the theft, although ,this did not happen. Some could also say burglary because of their state of mind, entering a building or part of a building as a trespasser , with the intent to steal , s9 Theft Act?
Simon and Lazio. Carrying knives in a public place is an offence, they are offensive weapons per se. Also , they do not have a reasonable excuse or lawful authority to have them. There is an act for this. maybe Criminal Justice Act?
Simon . Blackmail and maybe Assault? Forcing Roberta to participate in the crime against her will. Also threatening harm i.e apprehension of immediate unlawful force?
Roberta , aiding the theft/burglary? There was no theft/burglary but she knowingly helped people she knew were planning to steal. She was under duress though.Duress of circumstances perhaps?
This is very rough but good luck