Adding new S3 bucket to existing distribution

Hi, first post here so please excuse my lack of knowledge of AWS.

I have just taken over support & development of a site that is hosted in AWS. It has been stripped out of a larger group of sites and resources that were acquired in a recent company takeover and is mostly working okay. I have scant documentation on the AWS setup and to me it seems to be overly complicated. For background I am much more of a developer than a sysadmin or architect and I only have experience of Azure previously but anyway, onto my issue...

So there is an S3 bucket that is currently being served through a CloudFront distribution for CDN type purposes and this works fine. For reasons I will leave out (but it's a must) I need to "rename" the bucket, but I believe to do this I must create a new bucket and sync the content over. I have done this so currently have 2 buckets with the same content and exact same permissions etc.

Links direct to the new S3 bucket work fine but links through the CloudFront cdn are broken. e.g.:

• https://public-forcesreunited.s3.amazonaws.com/fr-website-assets/images/logos/armed-forces-services-logos/british-army-logo-359-x-601.png works.

• https://dmffixln4zsgf.cloudfront.net/fr/s3/public-forcesreunited/fr-website-assets/images/logos/armed-forces-services-logos/british-army-logo-359-x-601.png doesn't work, and comes back with {"response":"No config entry found for account key / file source root combination"}.

So I'm guessing that somewhere there is a link to the existing S3 bucket and I need to configure the new bucket too, but I'm really struggling to find out where. The CloudFront distribution https://dmffixln4zsgf.cloudfront.net has just one Origin configured which has the domain cloud-front-web-proxy-1738297328.eu-west-1.elb.amazonaws.com. So this must be an "Elastic Load Balancer"? I've had a look at this in the EC2 -> Load Balancers page and cannot see any linking to the original S3 bucket.

Could anyone suggest any further places to look please?