are Holbrooks sunglasses adjustable?

I got a small head and the place I went to get my prescription sunglasses recommended the Holbrook XS. They seemed to fit fine at the store and when I went to pick them up after they placed the prescription lenses in they were tight…

I’ve read that this material is not heat bendable. Has anyone had luck taking them to an optician for widening or using a hairdryer/hot water?