Markup Validation Errors

Hello,
I’ve recently set-up my WordPress site using a child theme based on the Twenty Thirteen theme.

I’m now trying to correct any errors using the ‘Markup Validation Service Website’.

It’s reporting both ‘Duplicate attribute id.’ and ‘Duplicate attribute class.’ errors.
I’m assuming these are related to having set-up a child theme – maybe they are duplicate from the original theme?

I’m really struggling to get rid of these errors. I’m fairly new to WordPress, so would really appreciate some help.

The errors are shown at this address (it’s only the first two I’m worried about at this stage)

Again, any help much appreciated.

[Moderator Note: No bumping. If it’s that urgent, consider hiring someone.]