Packing and unpacking boxes for your house is not usually included by default when you book a removalist. This is a service that needs to be booked separately (you can do this through Muval) or done yourself, and is best arranged for a day or two before your removalist is scheduled to do your uplift.
In our experience, people always dramatically under estimate the time it takes to pack their house, and it's usually one of the most burdensome tasks of moving! If you're packing yourself, make sure you start early and do a couple of boxes a day. Otherwise, save yourself the hassle and book packing services through Muval. Your future self will thank you.