Welcome to OpenStreetMap and thank you for all the edits you're making around Barking.

When a business or amenity is no longer in use, as an alternative to using 'disused' as a key, there's also the option of using it as a lifecycle prefix, e.g. 'healthcare=doctor' -> 'disused:healthcare=doctor'.
https://wiki.openstreetmap.org/wiki/Lifecycle_prefix