where in the DB can i set the Hardware Health Polling override to True

I may be wrong, but I suspect there is no value in the database for the checkbox alone. I suspect that when these entries are in the database, the checkbox gets ticked automatically.

Could you try to test this theory by manually creating an entry using Database Manager and checking if the checkbox is ticked?

Hello,

This is in the NodeSettings table. For example one of mine I did as a test is as below. This doesn't appear until its set so it wouldn't be an update statement. 

NodeID   SettingName                                          SettingValue     NodeSettingID
3143       HardwareHealth-StatisticsPollInterval   11                      1045739

So, i have just run some tests using Database Manager and ive been able to use INSERT INTO to add the custom hardware health and Polling frequenies into the NodeSettings Table and it is showing in the Node Details GUI with the Override Box checked and the new value. I thought i'd test it first without asigning an ID to it and this worked well and once in the Table it has asigned it an ID automatically. 

Check here on how you could create the entry in NodeSettings if it didn't exist via script: thwack.solarwinds.com/.../how-to-update-settingvalue-in-nodesettings-table.

Or here for CRUD: solarwinds.github.io/.../