[Uncle Bulgaria]

From previous experience with similar sorts of handles, I'd surmise that there's a screw inside that will allow the whole cap to come off, and from your photos I'd also guess the strip just slides into the handle surround. If this is so, sliding it out and using it as a templet should suffice. If it's spring steel, then strips of varying sizes are available for a few pounds on eBay. Alternatively, it could be cut from an old saw with some decent snips?