I can only assume I'm making some silly mistake here as it seems so obvious this ought to work :-S
I have a torch, in my inventory. It is set to be a weak lightsource to start with.
I have some batteries. When I put the batteries in the torch, I run a script that includes:
SetObjectLightstrength (torch, "strong")
And I'm pretty sure it runs that, because it does also print the message that is right next to it in the code.
I then walk in the cellar, where it is Dark.
But I get the "Dark" description, not the light one. And to confirm the darkness of it, I can't examine any objects that are in the cellar but not set to be weak lightsources.
It would seem my torch doesn't work. I even took out the batteries and gave the ends a rub to make sure they worked

(and checked the debugger and checked that its attribute was set to Strong, which it was.)
Is there some noob mistake I've made to explain why my torch doesn't work?
psy