If you went the GVC and OA route (which I suppose would be the reasonably expected option for a commercial operator to take) then as far as I understand it, nothing would change at all come 2026 as this would be entirely separate to any other rules.
As I understand it, you would essentially be writing your OWN rules which you agree to abide by, and then the CAA either approve them or deny them.
So you would write something like: I intend to fly only drone(s) of xxx weight, over industrial buildings, and I intend to keep xxx distance from uninvolved people and I’m going to do x y z to minimise the risks, and here are my risk assessments. Or something like that.
But I don’t see any reason why you couldn’t do the A2 for now, and provided you keep the prescribed distance from uninvolved people AND of course have the required insurance (required for any commercial drone work regardless) and abide by GDPR etc. and wait to see how the rules change between now and 2026. Fair chance however you would need to buy a new drone that has a class marking at some point.
Also worth checking which drones are considered ‘transitional’ - I believe there’s a limit about when they came to market.
ALSO - worth completing feedback for the CAA review of the rules (deadline is today, so not sure if it will still let you). That way you can have your say about how they’re changing the rules.