If an external wall cladding system requires remedial work then the valuer should take this into consideration in their valuation. A valuation will only be possible if the costs of the work are clear and there is a timeline for works to be completed. Lenders are unlikely to lend until remedial work has been completed, but some may choose to do so with retentions based on what they consider the risk to be.
The EWS assessment is for the building owner to oversee, but the resulting form should be available on request to all occupants in that block in the interests of transparency.