Paging the pottery experts

I’m trying to identify some of my aunt’s chinaware. The insignia on the back of the plate looks very much like Hicks & Meigh. See also here. You may need to scroll down for both links.

Just in case it’s not visible on the pictures, the back of the plate has the number 5125 top centre. There is no maker’s mark on the dish, but it has the number 4 over the number 478 bottom centre.

The problem I have is that the dates for Hicks & Meigh (1820s) don’t match with the date for when I think the banquet was given (1860s).

Is there an knowledgeable Doper who can confirm this? Or tell me who the manufacturer really was?

I’ve just had an email from Wedgwood, who now own Hicks & Meigh, telling me that their museum is closed. Not very helpful.