[ESS] How do I customise the frame split when I run a line of R from ESS?

[Chris Evans]

I am running Emacs with ESS both installed from the Ubuntu 12.04 
defaults.  Help says Emacs is:

"GNU Emacs 23.3.1 (i686-pc-linux-gnu, GTK+ Version 2.24.10)
  of 2012-03-25 on roseapple, modified by Debian"

ESS is ESS version 12.04-4

The default behaviour when I run a line of code from the icon in ESS 
seems to be a vertical split.  I'd love to get back to what I'm used to 
which is a horizontal split.  I thought I could find .emacs and edit 
that but I'm failing at square one: I can't find any .emacs file.  Using 
find seems to confirm that there isn't one which seems bizarre.

Can anyone help me?!

Many thanks in advance,

Chris

---
Chris Evans <chris at psyctc.org> Skype: chris-psyctc
Consultant Psychiatrist in Psychotherapy, Notts. PDD network;
Professor, Psychotherapy, Nottingham University
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