Do you need building regulations certificate for replacement radiators?

[HuckleberryGin]

We've replaced all the radiators in our house at various stages. Old house, originals were heavy cast iron things. Our buyers are asking for a building regs certificate, which we don't have. I have all the others and am pretty careful at keeping this stuff, so don't think we ever received one.

Is it essential to have building regs for replacing radiators?

I think you need building regs if you add extra radiators to a heating system, but not for replacement?

www.gov.uk/building-regulations-approval/when-you-need-approval

I've checked with solicitor and plumber and they both say not needed. Plumber says he would have given one if you needed one.

This bloody buyer is doing my nut in.