Definitely agree about it being 'Tess' - I'd mentally hung myself on
it being an old-ish variety and didn't consider it could be more
modern, let alone one of David Austin's varieties. I haven't grown it
and think I've only seen it once, but not at close hand. A rummage
through some catalogues I've got would have revealed it, but I didn't
think. A working weekend prevented me from coming over for that cup
of tea Sacha, but the urge for chocolate fudge cake is getting a bit
to strong to resist. Besides, I've got a cracking near-hardy (hardy
for me) Begonia for you to try.