Initial model cube name fix

[stephen-riggs]

I found I had this uncommitted from a while ago. It's a direct bug in the user-supplied initial model logic

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 53.31%. Comparing base (975c2f3) to head (1ba5c93).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #838      +/-   ##
==========================================
- Coverage   53.31%   53.31%   -0.01%     
==========================================
  Files         101      101              
  Lines       10933    10934       +1     
  Branches     1452     1452              
==========================================
  Hits         5829     5829              
- Misses       4788     4789       +1     
  Partials      316      316              

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[tieneupin]

Yep, looks fine! Does this urgently need to go in? Would it be too arduous to add a test for this?