Given the heavier bi-mode units with diesel and electric traction had to be procured in order to ensure a service could operate prior to completion of the delayed GW route electrification, could these units be switched to the MML in future and be replaced by pure electric Class 800 once the GW routes to Bristol and Cardiff are fully electrified ?
No, the way the contract works means that these units are specifically for GWML core services until the end of contract. Once the wiring is finished, the engines can be removed and they can return to service as pure EMUs, but they won't be moving around.