Davinci E3D mount with extruder upgrade

Since my Davinci 1.0's stock extruder idler became worn down and unuseable, I've been looking for an alternative extruder but there aren't too many options out there.
I tried a printed extruder which uses a bearing as an idler which worked well but it means the extruder stepper is only attached to the carriage by 2 screws.
So I thought I'd have a go at designing a mod that incorporates the E3D hotend mount plus a replacement mk8 style extruder in one part making the whole thing much more secur