Resealing roof joint - help required re: methodology and mystery of different sides having different arrangements...

[Sibsbibs]

And if I’m doing the egg shaped side bits separately, I’m wondering if something like this might be suitable and but up to existing strip, once I’ve rebedded?

White Silicone Rubber Strip

White silicone rubber strip available in various widths and thicknesses and supplied in 5 metre lengths. Silicone has an excellent resistance to ozone, oxidation, ultraviolet light, corona discharge, cosmic radiation, ionising radiation and weathering in general. All of these properties make...

shop.deltarubber.co.uk

 

[Terry]

Hi the gungy strip will more than likely be mastic on a roll and not a rubber seal leaking out.
Never used Silicon strip so no idea if it's any good or long it will last.
I would stick with what I know works
You can always simply reseal down each side without removing it .