These 50 pin small edge connector male-to-male adapter boards may be handy to some users.
https://www.simulant.uk/shop/Amstrad-CPC-Edge-Connector-Male-to-Male-Edge-to-Edge-straight-through-pcb (https://www.simulant.uk/shop/Amstrad-CPC-Edge-Connector-Male-to-Male-Edge-to-Edge-straight-through-pcb)
They let you join two female ribbon cables together or you have an expansion that already has a ribbon on with a 2nd female slot you can use them to then connect another expansion.