affliliated is when you are a member of the bsja. you basically pay an annual membership fee and there are affiliated sj classes that you work your way up - www.bsja.co.uk
may help explain it a bit better as i'm allowing NR to distract me from my essay so my brains a bit fuzzy!oh an dyou win monies as prizes and qualify for big events such as HOYS.
unaffiliated is obviously for non-members. these will be locally organised shows, agrucultural shows, yard show, RC/PC show's etc where everyone can take part.