Added your method to Simple.pm and a print $sheet->sheet_name to the script shown in the original post.

The sheet names appear in the correct order but the contents do not. Specifically, I get:

name = sheet 1

contents = sheet 4

name = sheet 2

contents = sheet 2

name = sheet 3

contents = sheet 3

name = sheet 4

contents = empty

It's the contents of sheet 1 I'm interested in but can't find. This is like the test with Spreadsheet::ParseExcel above but I was a bit vague (inaccurate) there.

How to solve my immediate issue is one thing but it's of course more interesting to figure out if this has identified a general bug. I'll play with Data::Dumper, etc to see if anything interesting comes up but not sure how far I'll get into the module source code...