Domain forwarding from naked domain not working

You don't have a root record for heat-consulting.co.uk. Please check this example link. https://support.dnsimple.com/articles/common-dns-records/#1-root-domain-examplecom

You can update it in your DNS settings, wherever the zone record is hosted. Here is what its resolving right now. www.heat-consulting.co.uk, looks OK but not for heat-consulting.co.uk

nslookup www.heat-consulting.co.uk
Server:  UnKnown
Address:  192.168.86.1

Non-authoritative answer:
Name:    d15u997s7fbj2e.cloudfront.net
Addresses:  2600:9000:20a6:6a00:c:da68:1180:93a1
          2600:9000:20a6:800:c:da68:1180:93a1
          2600:9000:20a6:e400:c:da68:1180:93a1
          2600:9000:20a6:a00:c:da68:1180:93a1
          2600:9000:20a6:d000:c:da68:1180:93a1
          2600:9000:20a6:8600:c:da68:1180:93a1
          2600:9000:20a6:e800:c:da68:1180:93a1
          2600:9000:20a6:ec00:c:da68:1180:93a1
          99.84.238.183
          99.84.238.98
          99.84.238.162
          99.84.238.131
Aliases:  www.heat-consulting.co.uk



nslookup heat-consulting.co.uk
Server:  UnKnown
Address:  192.168.86.1

Non-authoritative answer:
Name:    heat-consulting.co.uk
Address:  94.136.40.82

Hello!

I probed the DNS records for www.consulting.co.uk and consulting.co.uk

$ host heat-consulting.co.uk 
heat-consulting.co.uk has address 94.136.40.82
heat-consulting.co.uk mail is handled by 10 mx0.123-reg.co.uk.
heat-consulting.co.uk mail is handled by 20 mx1.123-reg.co.uk.

$ host www.heat-consulting.co.uk 
www.heat-consulting.co.uk is an alias for d15u997s7fbj2e.cloudfront.net.
d15u997s7fbj2e.cloudfront.net has address 99.84.208.105
d15u997s7fbj2e.cloudfront.net has address 99.84.208.102
d15u997s7fbj2e.cloudfront.net has address 99.84.208.3
d15u997s7fbj2e.cloudfront.net has address 99.84.208.56

The root domain heat-consulting.co.uk is not pointing to AWS Amplify. You should configure the root domain to point to your AWS Amplify hosted application and then add the other sub-domains (i.e.: www.heat-consulting.co.uk)

The following documentation outlines the steps you need to follow to configure the root domain: https://docs.aws.amazon.com/amplify/latest/userguide/to-add-a-custom-domain-managed-by-a-third-party-dns-provider.html