The bolt was cut off, or sometimes just cut part way through, bent then the gap welded up.
And of course, there's the old joke, if the bolt handle hits the scope, mount the scope
higher...
Unless you think the Boys Rifle was a several feet long .55 caliber anti tank rifle...
If you aren't wedded to the idea of a model 70 style swing wing safety, the swap to a Mauser scope safety is simple and only requires replacement of the wing. Numrich sold a decent one for a long time, might still sell them. I've put them on a number of Mausers and they work well enough.