TR5 and left hand chassis

[Brad20j]

I'm getting set up to build a left handed Haynes Roadster in NY. I obviously have the book, and I've seen the drawings posted on another thread about the left hand drive chassis.

I'm wondering, however, what's the purpose of TR5 (the diagonal that extends on one side of the engine bay)? Should this tube get switched to the left side of the car in a LHD setup? It looks like it should extend from TT12 (the top longitudinal tube on the inner side of the passenger footwell), even if TT12 were switched over to the left side.

Is the position of TR5 dependent also on what engine is used? Would it interfere with certain engines if repositioned to the left side?

Thanks,
Brad