Since you offered 
Is having my Web Shield heuristics set to normal ok? I have not changed any of the heuristics in avast! free.
I have, however, gone through all the settings to make sure “Scan for PUPs” is ticked and that the default “Actions” for PUP and Suspicious is: Ask > Repair > Move To Chest (although for Web Shield it is just “Ask”). For Virus though its: Repair > Move To Chest > Delete (with Web Shield set to “Abort connection”).
Is this ok or am I leaving myself open?