If you pay the £1,800 access fee, design build and test a working adaptor, and work with Tesla to get it approved I'm sure it's possible. Bear in mind though superchargers are so far apart only the outlander can get between them, and it's restricted to about 20kw charge rate, not making much use of the 135kw available from the supercharger.Why should Tesla owners get to have a.Chademo adaptor? No really you have the expanding super charger network, surely this should be your means of charging.
If this is happening there should be an adaptor for a super charge to CHAdeMO, honestly it should work both ways!!!
As a non Tesla owner it seems you're all having your cake and eating it.