Despite being ticked in options>Select columns, the manager does not display elapsed time. All other options appear when checked. Should I raise an issue over at git-hub or wait for a few updates to see if it resolves?

I've not seen any traffic about changes in that area. 'Elapsed time' has been around since GPUs were introduced, and my version 8.1.0 (probably many months older than your build) is showing it.

Check you haven't mistakenly set it to zero width (hidden file '.BOINC Manager' in your home folder). You should see a section 'Tasks' looking like:

[Tasks]
SortColumn=-1
ReverseSortOrder=0
ColumnOrder=Project;Progress;Status;Elapsed;Remaining (estimated);Deadline;Application;Name
HiddenColumns=Estimated Completion;Completion Before Deadline
ActiveTasksOnly=0
[Tasks/Project]
Width=125
[Tasks/Progress]
Width=66
[Tasks/Status]
Width=303
[Tasks/Elapsed]
Width=80
[Tasks/Remaining\ (estimated)]
Width=100
[Tasks/Deadline]
Width=212
[Tasks/Application]
Width=214
[Tasks/Name]
Width=475
[Tasks/Estimated\ Completion]
Width=150
[Tasks/Completion\ Before\ Deadline]
Width=150

If that's not it, report it.

Check you haven't mistakenly set it to zero width (hidden file '.BOINC Manager' in your home folder)

Thanks Richard. It was set to 7 and I changed that to 70 which brought it back. I had previously tried searching for the tabs to drag it back thinking your explanation was the solution but obviously didn't find the right ones.