Sun,
I wouldn't normally call TortoiseSVN a reporting tool. However, as a general answer, information in Blue Prism is stored in the database unless it is exported. To link it to an external versioning system you would have two main options:
1) Connect whatever system directly to the database tables and monitor/version those, possibly using triggers. I've never personally seen this done, but there's no reason why it wouldn't work.
2) Export BP code as an XML or a Release and utilize source control against the exported code.
In both cases, all relevant information is stored as human-readable columns and/or XML, so you could use straightforward DIFF to see changes.