New key to stoneflies from FBA

Hello. Has anyone bought the new stonefly key produced by the Freshwater Biological Association? I’ve been getting on fine with the 1977 one and as far as I know there has only been one additional species in the last 45 years, so I’m wondering if it is worth getting the new one. It has colour pictures and more than twice as many pages, but at 45 times the price (55x if you buy it from NHBS), I’m hesitant.