*** M E M O R U M ***

I see that there's a modified SDX on eBay at the moment:

https://www.ebay.co.uk/itm/Memotech-SDX ... SwIOxepqEg

Yes, it has a user mod to allow the 56 column CP/M ROM or the SDX ROM to be selected using the switch on the side.

A bit clunky but it works as guess

Regards
Dave