You could use a double flare to make a union in the straight section to splice onto a section of pipe you bought locally to avoid needing to source bubble flare tool especially if you have pipe with a bubble flare on one side.
The green are all bubble flares. Since you can buy sections of pipe with bubble flare you could buy a single piece with two ends long enough to replace the yellow sections. Reuse the 12mm from the 1-3 joint (and the other as well if needed) then cut the lines and splice with an sae union and double flare. (Blue on diagram) That is a single day from local parts solution.
Make sure the union is double flare and you might want to take a permanent marker and make a note to the next mechanic that is a double flare union.