Another speed sensor thread

Seems like a reasonably common issue but the speedo has stopped working on my Monster 796. It was intermittent, now digital gauge sits at 0. I've fallen at the first hurdle and struggling to remove the sensor, any tips for accessing the hex head screw that attaches the sensor. The swing arm gets in the way when lining up an Allen key and I fear I'm rounding off the head. I'll try and upload a picture separately. Thanks!