UK Mem contactor

[peter dennis]

Can a mem AA3 Contactor be replaced with an up to date eaton mem or similar in a mem 1980s consumer unit
How do I attach photos

 

[brianmoooore]

Is the AA3 the one that mounts on the DIN rail in a consumer unit, and looks from the front like a MCB with no toggle?
The modern version is branded "Eaton MEM". CR2020230v for a 20A double pole version.