The number is a British (UK) registration number from between 1892 and 1893. Even if you had access to the UK registration archives it is doubtful you would find the maker of the item as such registrations were often made by a retailer/distributor or legal UK representative of the German maker. In addition, the red addition is no German mark.

The registration number indicates that this ceramic piece is or was under a design patent !! I am not sure but I think the Rt. hand mark may be a trademark rather than a manufacturers mark !! You have to search differently for those !! Still looking !!