How to measure
Note the length of both sides and the depth of the chaise. A full photo is more useful than close-ups without scale. Tell us whether the modules separate and which rear surfaces are accessible.
Storage and sofa-bed sections
Storage compartments, pull-out beds and loose back cushions are not captured by external dimensions alone. List these in the quote. Mechanisms, metal parts and electrical components need protection from moisture; furniture should not be dismantled without agreement.
Access and drying
Clear the route to the sofa. Do not move heavy modules unnecessarily: first agree which sides need cleaning. Large upholstered sections can dry unevenly. Check seams and thick cushions before pushing everything back together.