The comparison is the point
An inventory on its own proves very little. An inventory compared against a check-out on the same structure, item by item, is what turns "the carpet is ruined" into a specific, dated, evidenced difference.
Templates
There are ready-made room templates covering the usual UK property types, so you are ticking and photographing rather than inventing a structure at the door.
Which check-in gets used
The one from the start of the tenancy you are ending, not the most recent one on the property. That distinction matters on a re-let and it is handled for you.
