You were right it is indeed a mess - what a nightmare.

Personnally i would strip it out and start again.

The basic principal of the brake system is they run as follows:-

Line 1 (top pipe nearest front of car) from master cylinder to t piece - t piece splits to front o/s and rear n/s.
Line 2 (bottom pipe nearest the servo) from master cylinder to t piece - t piece splits to front n/s and rear o/s.

The line should never supply the same side and they never supply either both front or both rears - hence why i think you have problems.

Some pics of the lines i created on mine (ABS removed)