Our removals/packers were complete stars. They kept us calm when we still hadn't completed by 4pm and once we had the keys they'd put every piece of furniture and every box exactly where we wanted it, in under 90 mins.
They packed far better than we would have had the time/patience to do. Had nifty wardrobe boxes so clothes were packed on hangers, things in drawers were wrapped for protection but left in drawers so unpacking was easy, everything was packed and labelled logically and not a single thing was broken.
They dismantled and put together the beds/cot and plumbed the washing machine. They even fixed a chest of drawers they noticed was broken.
We were unpacked in less than 48 hours, mainly because of the way they'd packed.
Pack essentials in your car (few clothes, overnight stuff, bed linen, kids favourite toys, potties, nappies, essential cutlery/crockery, kettle, bottle opener, paperwork, chargers, etc ).
And definitely declutter, especially loft/garage/shed.