This is in fact a very complicated difficult question. What is dumb, is that is should be so. Although I hate to, I will add to the considerable body of literature on this subject.
The answer depends entirely on whether you have one of the older straps, which slips, obviously and fast, or one of the newer, which are said to "not quite" slip, barely maintaining the specified weight and hardly an ounce more.
My wife's 8x5x42 EL unfortunately fell into the first category. In this case, cutting off the rubber-tipped ends to get them out of the way can, and actually has, resulted in the bino slipping free and crashing to the ground.
In the second case, trimming the strap "MIGHT" work, and good luck to you.
I advocate the "cut and burn" method. Cut it up into tiny pieces, and throw them into the fire. Buy a Optec strap, and have "Swarovski Optik" embroidered on it at a local custom sporting goods store that does bowling shirts. Or is bowling something different in England?
But, save the cute little hawks (habichts, I believe). Seems like they could be turned into nice earrings.
Ron