Landed property this writer originally secured in valley (7)

I haven't cracked this one yet — but the brilliant team at Times for the Times have:

ME (this writer) + S{ecured} [originally] contained by [secured in] DENE (valley). This was the clue mentioned in my intro that I failed to solve. Shame, because it’s quite an unusual word that I happen to know rather well from the days when I used to read conveyancing documents for a living.