Hello from Seattle!
I'm in the same situation as you, Toompah. I ordered from my dealer here the R&M Charger GX Rohloff HS -- mainly choosing the GX so I could get that fantastic dark yellow "Curry" color.
R&M told my dealer that color was no longer available in the 49-cm frame size I need. So I settled for black, planning to do a powder coating this winter.
Then my dealer told me R&M had said the latest batch of Charger frames was somehow deficient and that the company proposed just what it proposed to you: the Supercharger GX Rohloff HS instead, at the same price as the Charger. Of course I agreed.
Mine (probably like yours) is slated to be built in Week 30 (July 23-29) and to be delivered via air freight (paid entirely by R&M because of the change) during the week of August 4.
I feel there's some uncertainty as to exactly what components the bikes will ship with. Some have suggested, e.g., that they might include electronic shifting. So the following list may be inexact or incomplete. But -- for the obesessing pleasure of you, me and possibly others -- it sets out the differences between the Charger GX Rohloff HS and the Supercharger GX Roholoff HS.
The first column shows features of the Supercharger, the second shows those of the Charger, and the symbol (+, - or ~) indicates whether the change appears or has been reviewed as being better, worse or a wash, respectively. (The "~" is also used when no reviews could be found.) These are taken from the R&M 2018 USA catalog.
If the UK catalog reflects differences, I'd love to know about them. If you disagree with the direction of the changes (+, - or ~), I'd also like to hear your opinions on that. Also if you have items to add.
Supercharger Charger Change
Belt drive Chain drive ~ (cleaner; less efficient)
Magura MT4 brakes Shimano Deore XT -
Busch & Muller Lumotec Supernova E3 +
IQ-X E front light
26.8kg/59.1lb 25.7/56.7 -
1.66-8.84m gearing 1.69-9.04 ~
No apparent Ergon GP3 Grips present -
handlebar grips*
_________
*Speculation