Do I need a new gas safety certificate after repairs?

Hi, I need some advice regarding a failed gas safety certificate on a boiler and the hob on my rental property.

I have Home Serve cover and I organised a British Gas engineer to carry out a gas safety inspection on a property which unfortunately failed.

I have since had the boiler repaired and the hob replaced within 28 days of the gas-safe inspection. I spoke to the British Gas representative to request a re-test. They informed me that if they visit the property again, they will charge me again for a retest gas safety certificate.

However, they advised I do not need to get another gas safety certificate as I am allowed to marry all the documents together to confirm the work has been done.

I have looked online to check if this is the correct advice but I can’t find anything to confirm. Does the marrying of the certificates confirm that the appliances are safe legally for another year and I do not need another gas-safe certificate?

Thanks,

Rashpal