Generally, CUs  don't just spontaneously combust. Usually it's due to a poor termination causing overheating. So get someone who knows what they're doing to check that all the connections in the CU are at the right torque settings (or "suitably tight" in the absence of torque specifications), and that nothing looks to have overheated.

Hopefully the termination tightness testing was done by the person who did the EICR, there is a tick box on the model form for confirmation this has been done . Also, signs of overheating should have received a code.

Hopefully the termination tightness testing was done by the person who did the EICR, there is a tick box on the model form for confirmation this has been done . Also, signs of overheating should have received a code.