Even if the scope of your contract is just to replace the CU?
If you cannot expose and physically examine every mm of every circuit, do you on your EIC:
a) Tick all the boxes to say it complies in all respects with all the appropriate regulations, and hope that you are right?
b) Enter LIM?
c) Decide that if you are not installing a circuit you cannot be responsible for it, and not insist that all remedials must be sorted, and not try to write an EIC with a scope beyond the work that you do to replace the CU?
There are going to be an uncountable number of installations out there which do not comply with the 17th when a CU is changed. BS7671 has never been, and AFAIK is still not, retroactive, so people cannot be compelled to update their installations to the 17th just to enable their CU to be changed.
