Thanks to both of you, malone and jono. Perhaps I have been barking up the wrong tree. My home source of dictionary information is the 1994 edition of Chambers, so possibly not fully up to date.
I have just looked at Chambers online which is the latest 21st Century edition. Searching for trove brings the response that "no entries for trove were found". By coincidence, on the right hand side of the page is an advertisement for The Chambers Thesaurus which is described as "a veritable treasure-trove" (with hyphen). Checking back, I find that treasure-trove is listed in the main dictionary but nothing about trove alone.