I know the solid thin pipe is screwed inc but are the two rubber hoses connected to the distribution block on the right hand side of the mudguard screwed in or press/crimped fit as standard?
Some brake line kits are advertised as ‘4 line’ - I’m assuming they’d have to come with a new block if these are pressed in!
No need to buy new brake lines .,
Use the original resr, it fits no problem.
And use a 4 inch length of copper brake line bent to shape and fit it at the top brake line junction attached to the frame .. use the two threaded inserts from the old solid brake line on the new copper section