Small items are sent by Royal Mail Recorded Delivery. In the event you are not able to sign for delivery it will be held at your local Post Office for collection.
Larger items are shipped by DPD. You will receive an email on the day of delivery notifying you of the expected delivery time. If you can't be there to sign then you can reschedule online.
Small parcels are shipped by Royal Mail.
Large parcels are shipped by DPD.