Plan for two move dates, not one
A storage move normally includes collection, placement into storage and a later delivery. Provide the earliest and latest dates you know, along with both property addresses and an estimate of the stored volume.
The exact storage arrangement, availability, location and access terms must be confirmed before booking. These details can vary by job and timing.
Pack for the time in between
Label boxes clearly and keep an inventory of what goes into storage. Items you may need before final delivery should be identified separately, as access may depend on the confirmed arrangement.
Mention fragile, sensitive, oversized or high-value belongings in advance. Some items may need different packing or may not suit the available storage solution.