This isn't the answer you want, but it could be anything from weeks to months, and in reality it's probably driven by the urgency put on that site by the Telco. In reality it's much more likely to be months. Below is an idea of the tasks that might sit on a commissioning project plan, with the additional dimension that the various teams and contractors who will have a role in the delivery of this pole getting tasks for many different new cell sites.
Conclude arrangements for use of land/building for site. Do other necessary 'paperwork', inform OFCOM.
Order base station equipment (some items could be on long lead times due to chip shortage)
Foundations, ducts and mounts (pole and cabinets)
Order Power supply (could be long lead time and one that can be hard to influence)
Telecom circuits (if needed)
Check prerequisites have been met and basics are in place
Deliver and install pole
Deliver and install cabinet
First fix connect it all up and test basic power up
Commissioning before radio service, and out of service testing. Verify remote operational access for management, monitoring and alerting.
Make changes to adjacent cells to accommodate new cell (if needed) and test.
Commissioning into radio service with changes to adjacent cells for handover and handoff and test. Ensure sure is now actively monitored and alerted, test failure scenarios.
Handover from projects to operations with documentation.