We have noticed that a number of tests on our on premise pollers have not polled for a very long time.

Issue was not obvious. Only discovered when a critical application failed that wasn't identified in Site24x7

When you go to Admin, On-Premise Poller and then the respective poller, the list of tests all show green status (suggesting all is ok)

The last polled time only specifies a time and not the date.

Would it be possible to 

a) provide a status that indicates if a test has not been run for say 24 hours - red would indicate a polling issue with that test.

b) Change the Last Polled time to include the date (not just the time) e.g. 14:29 is meaningless