Just a question about changing Consumer Unit as they say that cutout fuse belongs to DNO so you should never try to interfer with it but honestly speaking all sparkys change CU as soon they pick up the job so am wondering how do they perform this if the CU does not have linked main switch?
Officially you call the DNO and they'll either send someone out to pull it (and fit an isolator if paid) or if your DNO operates such a scheme whereby thry give you authority based on your CPS membership - Some will let NICEIC pull and reaseal, others don't.
The way I see it EAWR trumps any 'thou shall not pull DNO fuse', but I would still notify of my intent, now if thry want to upgrade all th service heads for those with integral isolation turn great but until thry do, we have little option