Establish what the centre controls
Centres vary considerably. Some permit any inducted and insured contractor, some maintain an approved list, and some require tenancy cleaning to be arranged through the centre's own provider. Ask which applies before you contact anybody, because the answer determines whether you are running a comparison or accepting an arrangement. It usually takes one email to centre management to establish and it saves you from shortlisting providers you were never able to appoint.
Ask about access as well. Contractor entry outside trading hours often requires prior notification, a loading dock booking or an escort, and those constraints shape when cleaning can happen. A provider quoting without that information will propose an attendance time the centre will not permit, and the schedule will be rewritten before the arrangement has properly started and the price may need revising along with it.
