Flat consumer unit change.

[Guitarist]

Quoted from ESC guidance......

Q12. When carrying out electrical work on an installation forming part of a TN-C-S system, is it necessary to upgrade existing 6 mm² protective equipotential bonding to 10 mm²?
Not necessarily. If the existing 6 mm² bonding connects all the extraneous-conductive-parts to the main earthing terminal, has been in place for a significant time and shows no signs of thermal damage, then it may not require to be upgraded.

This is always the excuse people give for not upgrading any installation tho..... "It's been working fine like that for years".