Bug - Twine Visitor Site - Removing Activity via Admin removes ability to filter on Visits page

[mandsmandsmands]

Application: Visitor Website
Component: Activities and Visits
Env Version: Prod
OS: Win10
Browser: Chrome
User Account: Admin

Steps to recreate:

1. Log into Visitor Platform and the Admin side
2. Go to Activities and remove an existing activity which people have logged visits against, previously
3. Go to Visits page and bring up the drop-down "Activities" to try and select the activity you have just removed.
   Because as a user, you still want to see data/graphs against that activity.

Actual results:
Activity you have just removed is not on display in the drop-down, so you cannot filter with it.

Expected results:
All the Activities which are in the system, which logged visits against them should be brought up in the filter list - on this Visits page. Users should be able to filter on 'old' activities.