I think this could be the fridge here in the lower right hand side of the photo.Agreed
If it is castoff, this destroys his version, unless somehow he deposited it during the the cleaning process?
But otherwise, the blood from Grace, which should not have been a large amount, would have dried by the time he supposedly noticed
Castoff is suggestive of a violent struggle

Someone with bloody footprints walked around Auckland apartment where Grace Millane died | Daily Mail Online

Grace Millane murder trial: Traces of blood found on fridge in accused's room