In my humble opinion.
I do not think that there is any threat of prison or being accused of wilfully holding on to parcels, given that the neighbour in question put the address of SharonA on the parcels. This is a clear intent that she wants the post delivered to this address and must be a different situation to that of a neighbour accepting post that has a different address listed on it.
If you did decide to continue to accept parcels, this neighbour knows that she has addressed them to your property and I would have thought it must be her responsibility to pick them up from you, without you having to go to the trouble of taking them over to her.
If this was me, I would simply put a note through the door informing her that in future it is her responsibility to with you for delivery and to pick up all future parcels that have been delivered to your house with her name on them.
Happy Christmas all!
Sue