[HarryT]

Use:

{series}{series_index:0>2s| - | - }{title}

The problem with your version is that you'll get the hyphens appended to the title even if the book isn't in a series.

What I use personally is:

{series:|| }{series_index:0>2s|| - }{title}

Which, in your example, would give:

Vorkosigan 01 - Shards of Honor