Owning your own home

Envious of all these new houses but congrats!

Ours should be going on the market this week - excellent timing huh.

I have questions as a noob who has never sold somewhere before:

• Do we need to get paperwork to prove the boiler has been serviced and/or a gas safety certificate? The last paperwork we have is from March 2016 when the boiler was installed but it's thorough and includes building proof of building regs compliance. I did get a plumber to look at it recently when he was doing something else, he had a look and said it's golden but I have nothing on paper.
  
• I've got the same question about the electrics. Detailed paperwork from 2016, and the sticker on the (metal) consumer unit says it's next due to be inspected March 2021, but in reality it was looked at last year by a friendly spark when we had an RCD keep tripping because a few screws needed tightening.
  
• Last one is a bit embarrassing! We paid NHBC to do our building control stuff. I always presumed the dusty NHBC folder in the cellar had something in it - turns out not, apart from (minimal) evidence of three site visits. So we have no compliance certificate. Our architect arranged it and I just paid the invoice, so I think they had his name and address and I've also noticed that our house number is wrong on the invoice... Can I just call up NHBC and ask them to reissue the certificate?