Good morning, Tracy,

Thank you for contacting Mearto with your appraisal inquiry, and for the additional photographs. I can't make out a date mark so have dated this somewhat broadly; the value would not change with a more specific date.
This is Sheffield Silver, which is not solid sterling but a layer of silver over copper. It was a revolutionary new technique in the late 19th and early 20th centuries and created objects that had great durability at less cost. It is so named because a great deal of it was made in Sheffield, England, as yours was.
Here is a very recent sale of a Sheffield silver teapot that helped provide the basis for my value: https://www.invaluable.com/auction-lot/sheffield-silver-teapot-eb2492382e

Based on the photographs and information provided, and subject to examination, this is:

A Sheffield Silver teapot
Bears marks of Mark Willis & Son, Sheffield, England, probably first quarter 20th Century
5 inches high by 10 1/2 inches wide
Provenance: inherited from British grandmother
$100-150 (a fair-market value based on comparable sales at auction; retail or asking prices may vary)

Please let us know if you have additional items to appraise, and thank you for using Mearto.