I'm no expert on these either, but I'm pretty sure the reverse
reads CIVI-TAS-DVN-[ELM], for Durham, and I can't find a halfpenny or farthing for Durham in my old (1990) Seaby
's, so it is probably a penny.
reads [ED]WARRAN[G...] which (if I read Seabys correctly) suggests a type
10 of Edward I or type
11 of Edward II.
Hopefully someone more expert will correct me.