What Sonos products (make/model) are they exactly? Also, are you moving from a Country outside the UK to within the UK?...or are you saying you’re in the UK already and simply just moving/staying within the UK?

I am not sure if the products. They are Sonos boxes for built in speakers in several rooms of the house. I also have one Sonos Move. 
 

We are relocating within the UK. 

You’ve really got us guessing rather than being specific if you would tell us the models. 
By “boxes” do you mean complete units such as a Play:3 ? If so (there will be a label on the back or possibly the underside of them) you need the power cord. 
If they are built-in wall-or ceiling-speakers, fitted into “boxes” as a housing fitted into the cavities, you may need to consider them to be the type of item you need to leave in situ when you move (or else make good the holes when you remove them).

The Move will need its power/charging cable.