These must be some samples/subs with the better quality than the Rose collection. I have not seen yet Grenson Rose with channelled soles. The seller was selling some similar models a few months ago. I bought from this seller a pair of Grensons (Noble I think). He's always offering only a few items that start very low and arrive around 100 quid.
I bought exactly the same wholecuts from another ebay seller (kai33raj) last year. I do not remember the inner sole, but I have the feeling they were dark brown. They are definitely Masterpiece. Those pictures are not doing them justice.