If you are talking about a Tex Mag Lite, they are fairly common on Ebay uk. I'm sure Ike has them, but the uk ones tend to sell for pennies.
There isn't much to go wrong inside them. The main issue tends to be gummy grease in the switch itself. Take the cover off and hose it with WD-40.
The other problem is the rubber cancel wheel. Ike sells new reproduction ones.
1966 109 5 door wagon 300Tdi "spermaceti fueled"
1994 RRC LeWiB "ruining the air behind me"
All my troubles are Rover