Unfortunately Fiona Cooper DVD 1083 isn't in BGAFD and the girl doesn't look like any of the Ruths in the database. Nobody replied with much more information -- except for a few more pictures -- when someone there asked the same question a year or so ago: http://www.bgafd.co.uk/forum/read.php?f=2&i=141326&t=141326.
As you probably know, (just to make things more difficult) many girls in Fiona Cooper products go by names that are not used for other work they've done.