Hello PiedPiper,
The good news is that, as of July 2008, Oliver Brookes was alive, working, and apparently performing in the vicinity of Potsdam, New York.

The bad news is that, since then, he has apparently fallen off the radar.

Today, I compiled a time line of Brookes? post-Munrow career based upon what I found out about him via Google. I assume that the Oliver Brookes to whom the references in Google refer is the same Oliver Brookes who had performed with David Munrow. My assumption might be wrong, so my time line might not be correct. In addition, my time line is not comprehensive; rather, it provides just a brief overview of what I think Brookes has been doing since 1976. Here goes ...
Time line:
In 1977, James Tyler founded the London Early Music Group (please see:
www.usc.edu/schools/music/private/faculty/tyler.php). Brookes was a member of the group from 1977 until at least 1985 (and possibly beyond). You can read a November 21, 1985
Los Angeles Times concert review of the band, at:
http://articles.latimes.com/1985-11-21/entertainment/ca-2035_1In 1980 and 1981 Oliver Brookes spent periods as a musician in residence at the University of Western Australia. Source:
Australian journal of music education, issues 30-31, dated 1982, page 26.
In 1984, Brookes and Roxana Gundry founded the Roundelay Duo.
This, excerpted from a January 22, 2009 MIT University concert program:
In 1984 Ms Gundry formed the Roundelay Duo with Oliver Brookes to perform music of the medieval, renaissance and early baroque era, using historically accurate copies of early instruments.
Please see:
http://onigo.mit.edu/~dluca/meridians/CONCERT'09Jan/ConcertProgram.pdf, page 5.
In 1999, Roundelay appears to have been extant. Please see:
http://gfhandel.org/bleissa/pipe/piper.htmIn 2001, Brookes performed with Voces Intimae. Please see:
www.cefls.org/trailblazersummer2001.htm#VocesFrom 2000 to 2008 (and possibly beyond), Brookes has performed with Cantilena.
According to a New York state-based arts directory, "Cantilena features Brookes on viola de gamba and Clive Henery on harpsichord, performing a wide spectrum of musical styles. Cantilena also offers demonstrations of medieval and baroque instruments for various age groups."
Please see:
www.slcartscouncil.org/index.php?option=com_sobi2&letter=C&Itemid=168A note about Clive Henery: Henery is a Durham, England-born retired professor emeritus of the Crane School of Music, at SUNY University, in Potsdam, New York, and has a background in music history and keyboard instruments. His wife, Sandra, is a retired public school music teacher.
See a vintage 2000 photo of Brookes and Henery, at
www.cefls.org/trailblazerfall2000.htmSee a (vintage 2002?) photo of Brookes performing with Cantilena in Potsdam, New York, at
www.cefls.org/trailblazerfall2002.htm#OliverOn Tuesday, June 5, 2007, Brookes did a presentation with Clive and Sandra Henery, entitled Early Instruments and Intimate Voices.
Please see:
www.exploritas.org/ein/summary-ne.pdfIn July 2008, Brookes and Henery performed with Cantilena in the Potsdam (New York) Public Museum.
This, excerpted from the museum?s Fall 2008 newsletter:
July: ? Later in the month the museum hosted a concert by the group Cantilena with local harpsichordist Clive Henery and his wife Sandra on the viola de gamba and guest artist Oliver Brookes and Arlene Babich.
Please see the museum?s Fall 2008 newsletter, at:
www.potsdampublicmuseum.org/documents.php?docid=6I?m sure my time line has factual omissions and errors, so please feel free to post corrections on the board.
If I find more current information regarding Brookes, I?ll post it here.
Hope this helps!
Sarah