I suggest starting with the 1910 Valuation Office Survey (also known as the Lloyd George Doomsday Survey). This was compiled between 1910 and 1915 and provides a listing of all land in England and Wales over 1 acre in area. Probably the easiest site to use initially is
The Genealogist. This information can then be tied in to the tithe maps mentioned by
macwill, which cover an earlier period. Land registration was pretty hit and miss prior to the
Land Registration Act 1925, and the local county record office for the area where the land is located would be a good starting point. Given the timing of the mother's will, it's possible that a solicitor dealing with the mother's estate would have been mindful of the need to register the land (per the 1925 Act) and so that might give you a starting point. However there is no guarantee a. that it actually was registered with the local Land Registry, and b. that there will be any details about earlier ownership.
Do you understand the significance of the term 'settled land'? If not, take a look at the
Settled Land Act 1925, perhaps in conjunction with the Wikipedia article on the subject. The 1925 Act relaxed the old common law restrictions on strict settlements.
Both of the Acts mentioned were part of wider reforms of real property ownership during the mid 1920s.
Another piece of legislation which may have a bearing on the earlier ownership of the land is the
Married Women's Property Act 1882. This was the first time that (most) married women were allowed to own real property in their own names. This may apply to the mother if she inherited the land from her family's side, rather than from her husband. Due to the mention of settled land, she may have held the land in trust.
