Replace First Instance of Full Stop With Colon

Hi,

I prefer to have only one colon in my classical music file titles, in order to act as a clear delimiter for
work titles. However, I have discovered I have over 900 files with two colons, because of careless
tagging.

Therefore, I would like to know if it is possible to find the SECOND instance of a colon
in a file title and replace it with a full stop/period?

e.g. Symphony in A major, Op. 99: 1: Allegro

               needs to change to:

   Symphony in A major, Op. 99: 1. Allegro

With an action, this works:

Action type: Replace with regular expression
Field: TITLE
Regular expression: ^([^:]:[^:]):
Replace matches with: $1.

[ ] case-sensitive comparison

Why would you want any colons at all in a field that might be used as a file name?

I didn't think this would be possible, but you proved me wrong!. Thank you very much.
As to using separators in the file name, I foolishly allow iTunes to organise my file names,
but one day I hope to change that.

Regards.