Some of us have noticed some disruption to deliveries. There is general advice on the Royal Mail website here.
Some informal advice from one of our members is that around 40% of the staff are unable to work. If your regular postie is one who has to be off work, it will take someone else longer to sort the mail for your round and also to deliver it. In normal times two posties share a van so that is now impossible, and you may see some using bikes. If your round it being covered by a postie unfamiliar with your area, and also having to take on more than one round, then you will be lucky to have two deliveries in a week. The delivery of tracked items is being given priority so if you need to ensure delivery, send it ‘tracked’.