PPA, being 10% of yourcontact time, could be reduced (not cancelled) in weeks with an INSET. Your sickness absence could also reduce your entitlement that week BUT did you have to send them work for your classes on the day you were off? That would constitute planning for those sessions and you presumably started tackling the week's lessons in your previous PPA time. PPA time can be taken off- premises (more likely in Primary where an am or pm session can be timetabled for PPA BUT your time off sick cannot be allocated as as PPA time. Check out www.tda.gov.uk and put PPA or PPA regulations into the search box.