The Lambda is not valid for any of the supported regions.

The error you're encountering suggests there might be a region compatibility issue between your Lambda function and the service you're trying to connect it to (Alexa Smart Home skill).

There are a few potential causes for this error:

1. Region compatibility: While your Lambda function is in eu-west-2 (London), it's possible that Alexa Smart Home skills may only support specific AWS regions. You might need to create your Lambda function in a region that's explicitly supported by Alexa Smart Home integration.

2. Function URL limitations: If you're trying to use Lambda function URLs for this integration, note that function URLs are not supported in certain regions, though eu-west-2 is not listed among the unsupported regions.

3. Access permissions: Ensure that your Lambda function has the appropriate permissions to be invoked by the Alexa service. This would typically involve setting up the correct resource-based policy.

To resolve this issue, you could try:

• Creating your Lambda function in a different region that is known to be supported by Alexa Smart Home skills (such as us-east-1, which is commonly supported for many AWS service integrations)
• Checking the Alexa Smart Home documentation for specifically supported AWS regions
• Verifying that you've correctly configured the permissions for Alexa to invoke your Lambda function

If these steps don't resolve the issue, it might indeed be a backend issue that requires AWS Support assistance. You can open a support case under the "Account and billing" category to get help with this specific problem.
Sources
Creating and managing Lambda function URLs - AWS Lambda
My Lambda shows Access denied | AWS re:Post
Unknow Error when creating a Lambda Function | AWS re:Post

Verify if the function exists in the correct account and region aws lambda get-function --function-name Home_Assisant_TimGuyUK --region eu-west-2

Also, do you have a typo in the function name is it supposed to be Home_Assistant_TimGuyUK instead of Home_Assisant_TimGuyUK.