Bottom bracket shell in carbon frame

I have a fairly old carbon frame and the bottom bracket shell has become very badly corroded. One shop told me it was a bin job but would be great to hear if there is a reasonable way to replace the shell?

Carbon Bike Repair have looked at it and said they can’t do it (on the basis that they do the carbon bits of the frame and the shall is aluminium)

I guess I could send it back to the manufacturer but it’s well out of warranty and the mfr is in Italy so would prefer to look locally first

Thanks in advance!

Is the ali bit still firmly rooted within the carbon?

I've sent people to Andrew Armour/Eastside bikes in Edinburgh as they offer a ream out and bond in a sleeve service that can refresh frames. Not sure if he'll do it on a carbon/ali hybrid but worth asking.

Edit: Hew taps it out and uses a thread in insert. Bottom of the page https://eastsidebikes.com/repairs

It seems quite firmly in there but not sure it’s fully intact. Still, no harm in asking Eastside. Thanks for the suggestion

I second the Andy Armour suggestion. He's permanently repaired stacks of real hard-use bikes like this (think DIY-electric pedicabs and cargobikes).