We had a WC Group Leaders' meeting yesterday.
The returning officer asked if all candidates could ask their electorate to post their votes back to WC, and not to hand them in at a polling station.
Delivering your postal vote in person is perfectly legal but the returning officer is asking people to avoid doing so if possible. This is simply to reduce the number of people attending the polling stations.
Other than 'late' postal registrations everyone has hopefully had their postal vote packs (for WC and the PCC elections) by now.