The original frame mount design didn't line up right with my frame (there have been changes to the A8's frame design throughout its production run), so I designed a new one by starting with a chain link and building it up from there.
The initial installation had the cabling into the bed routed too high, cutting into my usable print area (especially with a 3DTouch on the left side of the carriage). I got some more room for the wiring by removing the plug body and shrink-wrapping the individual wires and contacts.
The bed-thermistor connection at the plug was bypassed with a 2-pin Dupont connector a while ago because an intermittent connection at the original connector was causing Marlin to kill my prints. This has also been routed under the cable chain.
Print the frame and hotbed mounts with at least 25% infill and two or three shells. Print 14 chain links (and maybe a few more as spares) with 10% infill and one shell for a lightweight but strong-enough chain that assembles easily and is very flexible.
It might not be a bad idea to replace the stock wiring with something more flexible, as the stock wiring is stiff enough that the chain rises above bed level when the bed is toward the back of the printer.
The hotbed mount should be printed in something temperature-tolerant, like PETG or ABS. The other components are printable in PLA.
This should also work in a right-side configuration if you mirror the mounting brackets in your slicer, but this configuration is untested.
I imported the original frame mount and a chain link into OpenSCAD to get the hole positions and the alignment of the chain link correct. I then added extruded rectangles to build up the new mount and cut out a crossbar on the chain link. The frame mount was deleted when complete, but the chain link was left in as it provides the attachment point for the chain.