I'm sorry, I am not an expert on the subject of the Grimwade potteries and cannot help with queries about tableware.

I have simply published this picture for the interest of those researching the history of Grimwade. The item was made at period when there was much experiment with lustre techniques and the inside surface of the nautilus shell has the colour and irridescence of a natural shell.

The naturalistic use of lustre and the restrained colour scheme make it a very pleasing example.

The base does not have a company stamp. The lower picture shows the applied registered design stamp (from which the piece was identified) and the scrawled initials  "W.M". The initials seem to bear a relationship to the pottery signatures of William Moorcroft but I have not been able to find any evidence that Moorcroft worked with the Grimwades.