So, post offices are open as they're deemed essential. But what post could individuals be sending that is essential? Are post offices still open for posting things, or only for their other services?
My FIL wants to post something, the post office is at the supermarket he needs to go to anyway for essential grocery shopping, but he's worried that posting his parcel isn't essential. MIL thinks that if the post office is open for posting things, it's fine for FIL to post it as no individual really posts essential things these days so if they're open they must accept that no one posting things will be posting anything essential. FIL is worried he'll get in trouble and is very keen to follow all rules.
His parcel definitely isn't essential, it's something he sold on eBay.
Can he post the parcel while at the supermarket he is definitely going to go to anyway for essential food (so it's not like he's making an extra trip out or anything).