With regards to your community payback, i have offenders work with me all the time. Depending on the probation's assessment of you, you will either go into a group session...working with others, fully supervised by a probation officer or go to a single placement. Single placements can either be working in a charity shop or working with me or my colleagues doing gardening. Work is for a minimum of 7 hours a day.
Keep your head down, be nice, do the work and it'll be a doddle. I've actually made some very good friends in the 4 years i've been doing it.