Could you clarify if this term relates to a , a cooking technique , or a historical reference ? Knowing the context (e.g., a book or a specific region) would help in providing a more accurate report. A timeline of food in Britain - English Heritage
There are several English heritage plants that have specific names, though none are "mature thumbs." You may be thinking of: english mature thumbs
: Significant features of the English Countryside , such as ancient oaks or mulberries. Could you clarify if this term relates to