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Could you provide a picture of the bottom mark?
By 1891, the words Doulton Burslem and England are shown, along with a coronet. Starting in 1902 following the king’s designation, a lion appears on the mark along with a crown.
Your set is from the period 1902-1927. Normally, the put the pattern name or number with the mark, however it is not your case. I tried to find the exact pattern name or number but I was unsuccessful, most likely that this pattern is not very common and it's nor in the registry. A pattern depicting landscape was quite common in the 1920s, even with some indian style, an example is the Royal Doulton Fox Hunting pattern.
Regarding the value of your item, I have just perform a market research of similar sold items as yours. I performed the research based upon the most recent finished auctions and private sells, so the value given is the real market value of your item. This is the only way to know the exact value of your unit.
The value will be in the range of 30-50$ for the pair of cup and saucer.
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