Having the HWS SLED on should not effect the interferometer, I added this into the guardian because we don't want the SLED running indefinately, but it is easy to turn it on and forget.  If the warning message is confusing we could remove it, or move it to a less obtrusive place.

Presumably this check is coming from the DIAG_MAIN node.  I think the important principle for that node should be that all the diagnostic checks should be actionable, in other words someone should get out of their chair and deal with whatever the notification is to make the notification stop.  If the plan is to leave the HWS SLED on, or it's not critical to shut it off, then it should be removed from DIAG_MAIN.

Maybe we can add a second DIAG node for not immediately actionalbe diagnostics, but my guess it that it will just be ignored, since by definition nothing there will be critical.