2 Questions: marking "sections" and automatic beaming

[Mark Gibbens]

I'm new to music publishing on linux, and have just transcribed a tune  
with Lilypond for the first time.

Here's the piece I'm working on:
http://flet.org/tests/The-New-Way-to-Bowden.ly
http://flet.org/tests/The-New-Way-to-Bowden.pdf

The automatic beaming seems not to be working well in the second-from-last  
bar of each repeat section.  The first time round, I've used manual  
beaming to fix it, but I wonder if there's anything I'm doing wrong to  
cause Lilypond not to beam those last 4 semi-quavers in the offending bars.

And also, I'm not sure of the correct musical terminology here, but I'd  
like to mark each repeated section with a number or letter - "[1]" or  
"[a]" - displayed above the stave at the start repeat bar-line.  Letters  
would probably make the most sense in the folk music context I'm working  
in.  But I couldn't find how I might do this in the documentation... any  
advice?

Many thanks,
Mark.