Lack of building regulations for boiler installation - we pay for the insurance indemnity cover?

The email from the solicitor reads:

“We have requested that they provide an insurance indemnity policy to cover this.

However, if they do not agree to provide this, we will obtain a draft and the cost will be accounted for on our draft completion statement prior to completion. It will be approximately £50-70.”

Does this mean we pay this charge for a certificate for the boiler installation that the sellers should have had?

We’re first time buyers, buying a property that’s gone through probate and it’s been straight forward so far. I’m hoping this isn’t a big enough deal to delay the process.