Alan,
I'm in the process of remote-ing my own DX. It has an NVR that I'm ditching. It's a bit temperamental starting anyway, as the NVR has trouble latching in.
Instead I'm just using a
single pole rotary switch from Toolstation. I stripped the radio-controlled remote down to the circuit board, and modified the switch box to fit it inside, alongside the rotary one.
So the rotary switch kills the DX (but doesn't completely isolate it), for bag changes, etc., and I'll put a big warning label on to warn that you must isolate it properly before trying to clear blockages.
I'm very surprised that the modules you have forget their programming: the ones I got (Maplins) had two little 4-way rotary switches, giving 16 combinations (there are four send channels on the remote, and four sets of on-off buttons). I haven't finished the mod yet, but I'll solder links on the pads where the switches connected to the board. The switching is done by a 3kW-capable relay, so should cope fine with the DX (it's not big - 10A max I think).
I looked at Bob's DOL starter circuit - it should handle the current with more leeway, but mine will fit on my DX better! Pics when I get a moment.
E.