Fibre cement corrugated sheets- wind damage repair

[IWalkLikeHimaMartian]

Some words of wisdom from those experienced with these materials would be appreciated.
My one open sided barn has suffered some wind damage to the roof, approx 5 meters across by approx 10 meters ridge to eaves. (About ¼ of one side )
The sheets are (from memory because I am out of UK at the present) 2or 3 metres long, possibly 3"/75 mm profile.
The property is insured, but for obvious reasons I will consider a repair myself.
I have an extending roof ladder, some battens and a scaffold to enable access, so no problems there.
I think there is minimal damage to timber roof structure, and any will be repaired as required.

One main question, is when on these sheets, do they support your weight, or is the roof ladder or battens a necessity? What is the, if any, limit of span between supports to support your weight?
Another question is what is the likely cost of sufficient sheets, fixings etc for repair?

There are also 3 or 4 that have cracked over time ( more than twenty years). How easy will it be to replace 1 here, 1 there, 1 over there, etc?

 

[Elastomeric]

You will need to spread your load over the roof, typically with youngman's or similar. Sheets should be 6ft long. It's also likely they have Asbestos content. New ones and fittings are available, if yours are fixed to timber, probably fixed with twist nails with a rubber washer.
Southern Sheeting should have all you require.