This is a set of three bird plates made by Minton porcleain of England and retailer by John Mortlock of London.
These were made especially for the Mortlock store by Minton in 1848. Mortlock operated from 1746 to 1930.
The hand written numbers on the back are pattern numbers of G28 and the line with the dot next to it is the date code for 1848.
These three Mintons plates were likely part of a custom ordered set, but along the way was parted out to different family members, lost, broken, etc and the remaining three were turned into hanging plates.
This set of three have a value of $110 each.
Some sites that I recommend for selling are Offerup.com (local), Varagesale.com (local) , Ioffer.com, Ebay and letgo.com (local).
You can also go to invaluable.com or liveauctioneers.com and search their directory for an auction house near you and consign to them.
To finish, I will need you to leave a feedback by clicking the stars. Bonuses are also welcome! Just click Leave a Review and the percentage-based bonus option should be there. Thanks!