The ones I have worked with are Rebel versions where the LED is mounted on a holder which made the job of replacement much easier. The PCBs use and adhesive pad and I do have a set of instructions for removal, but so far have worked inside the lamp.
I would not recommend anyone sending in a lamp that is working fine, wait until something goes then nothing to loose.
As a point of interest, the Stenlight is analogue controlled by means of reed switches and a little magnet. It uses a DC-DC converter which is very efficient. A lot about this on their website. Its honest technical fact not sales BS, so I bow to them.
Playing around with conventional buck drivers, there seems to be two basic issues.
1/ Falling output even at low levels with reducing battery voltage
2/ Poor efficiency at low output levels.
I am currently putting in a lot of lab time in Attempting, (note the "A" word") to produce a high output driver with analogue mode switching. I gave up at one point, but had some fresh ideas, so now back at it.
My Scorpion X12 is a popular and versatile lamp but the drivers I have been using are no longer available. So IF (the "I" word) I succeed, that will be the platform for the new driver.
I dont want to say too much in case the project goes bottom up. When I went for my black belt in Shotokan a few weeks ago I kept my trap shut in case I failed, when I passed, (a very good pass as well) I tell people.
Back to Stenlights, I know of a modified Stenlight which outputs 1000 lumens on turbo, I have to emphasise that this is nothing to do with me.
The Stens electronics have much of merit in their simplicity and efficiency.