The courier we use for UK delivery is DPD.
DPD's delivery hours vary depending on your area and address type. For residential addresses delivery times are from 7am to 10pm and for business addresses they are 9am to 6pm.
UPDATE: From 23/11/20 to 11/01/21 DPD will be withdrawing PRE 10:30am and PRE 12pm deliveries.
Weekday courier and Saturday courier will still be available.