It's on the Dutton Epoch label.  So near as I can tell some, though perhaps
not all, of the releases on this sublabel are not rereleases.  I would be
very much surprised if the Rubbra violin sonatas recording were- I know
of no recordings of the first and third violin sonatas before this date.
Moreover, iirc, the violinist and the pianist are modern.

(By the way, there is nothing, to my ears, 'Hindemithian', in response
to Mr.  Newberry, about the third sonata, and I say this as someone who
loves both composers but who can also tell the difference between them;
the Hindemith second string trio for example - one of my favorite works
of that period - is beautiful and open-spirited but recognizably Hindemith,
while the Rubbra sonata is different harmonically, texturally, in quality
of motion, and in most other senses I can imagine.  You may well be
right about the first sonata, which I do not know; it was unpublished to my
knowledge and is almost certainly receiving its first recording here.  I do
not like to disagree about this, since Hindemith 1930-50 is more or less my
favorite Hindemith, and a work I could compare to such music would be easy
to describe and to describe favorably; but the Rubbra, which (insofar as I
know it- 2nd and 3rd sonatas) I still recommend- is rather different, in my
opinion at least, the 3rd sonata especially.)

-Eric Schissel