Legate, I am sorry for not understanding your question, and presenting you with a rather childish response!
To answer your actual then, no, she did not make it up. And there is no reference to it in the trilogy. However knowing your question I flew to my copy of 'History of Middle Earth vol i' or 'The Return of the Shadow'.
And found the following quote amongst Christophers explanation of the error in the distance given by Merry that the Nazgûl would have to travel to cross the Brandywine.
"The main road within Buckland is described (on a rejected page only) as running 'from the Bridge to Standelf and Haysend.' Standelf is never mentioned in the text of LR, though marked on my father's map of the Shire and on both of mine; on all three the road stops there and does not continue to Haysend, which is not shown as a village or any sort of habitation.(5)" -
(HoME 6, The Return of the Shadow)
And
Aiwendil is spot on with her translation of the name, for in the note '(5)' is the following;
"5. Standelf means 'stone-quarry' (Old English stan-(ge)delf, surviving in the place-name Stonydelph in Warwickshire)." -
(HoME 6, The Return of the Shadow)