The reliable way to hire a tradesperson

I asked an electrician to do an EIRC certificate for my property, he said I need ".....18th Edition consumer unit including SPD and RCBO’s for final circuits" He explained that my meters are too far apart and new regulation mean they should be closer. Both meters are wall mounted, electric meter is at bottom of stairs entrance to flat and gas meter at the top of the stairs, 13 tread stairs. Can someone explain please. I don't have the money to spend, he has quoted £1000+vat

I have a 1970s, ex-council, terraced house. Home report states damaged sarking panels. Can these be repaired/replaced from inside the loft space or would it need to be from outside ie new roof?

I am due to have some skimming done in x3 bedrooms, all rooms are prepared but I would like to keep the existing skirting board and architrave and the man doing the job is happy with this. However my dad says it won’t be a good quality finish, time and money are what are holding me back having to replace them. What do other professionals think??