Nice. Didn't know that existed. I guess ignore my previous statement. Except the part where I said it's best as is😁
The ican MagCharger is a very good torch. Obviously it won't match a modern LED in output. But it has other qualities. The stock MagCharger bulb is quite nice if you want a tight throwy beam. I'd bet the old NiCd battery is knackered. You can get newer NiMh replacements. But if you fancy spicing it up a bit you can easily run AA's by means of AA to D cell serial adapters. Sanyo Eneloops are great and you can bump up the voltage by one cell for better performance.
I currently have a Phillips 5761 30w 6v bulb in mine running on 2 x LiFePo4 cells. It has a nice big beam, quite good beam distance and more than enough lumens to be very useful.