From what has been published so far I don't see any change to what we already have.
"Like-for-like repairs". It says that in the new rules these wont need to be notified to DVLA. But they wouldn't have been notified anyway. Would they? I mean if I repair an old car with a genuine like for like part then why would that have ever been notified to dvla?
The second 'new rule' refers to 'structural changes'. ie chassis or monocoque changes. This never used to apply to a Z3 rebody (our rebodies are cosmetic. Not structural) but now the new rule might affect us because structural changes could mean 'changes to the appearance or dimensions'. Which a rebody certainly would affect.
So, personally, I don't actually see what's changing.
It removes the doubt in the eyes of a random inspector.
If a car has a V5C that has a different name to BMW Z3, the assumption has to be that DVLA has been informed AND WERE HAPPY, especially if the date of change on the V5C is post 26/08/2025.
Previously, changes to monocoque would effectively write the car off, as it would need an IVA (see the electrified Mini that drilled a hole for the main battery cable). Now, if DVLA are happy that the hole doesn't affect the strength, the car can have the V5C amended without the need for an IVA.
It also means that old vehicles can be electrified - which will have been the main motivation of the change. We can take advantage.
The downside is that we have to inform DVLA of changes to the monocoque, but we do that anyway when we tell them about the rebody. The usual answer is "No Changes". Now, we can inform them, and I presume it will either go through on a nod, or will have to be inspected, but if it passes that inspection it will not need an IVA. If it fails the inspection, it would have failed an IVA anyway.