From what I heard is that it needs a complete replacement cab although they are inspecting the front carriage to check for any damage to the undercarriage.
So I would suspect that providing there is no serious damage to the undercarriage then Alstom could build a replacement cab however I have no idea how long this will take, a pity is the class
175's had gangways on the end then perhaps they could have copied what FGW have done to their class 158's as used 1 of the carriages to form a 3 carriage train til the 1st carriage is repaired.