First things first. I got into endless trouble from the engineers at Rolls-Royce for calling such things 'solid' pipes. They rightly pointed out that were it solid it wouldn't be a pipe at all and would be a bar. It's actually a 'rigid' pipe.I am sure that when on static display and any panels are off, the team could change that solid pipe for rubber.
The problem we had was that they appear to have lashed up the plumbing in desperation by hack sawing then gas welding a fitting to force the hose that once came from the abandoned fuel filter to go around a corner it just should never have gone around and that fix, if you can call it a fix,surely wouldn't have lasted long before they had to think again.
The situation now is that if you want an inch BSP fitting it must, for safety and regulatory reasons, come attached to a hose of a certain standard that, as pressures, loads and demands have increased with improved engineering, has grown much fatter and less bendy than what you got in 1966 and even less inclined to go around that impossible corner.
Given the state of the bodge it's likely their comparatively lightweight hose would have given in and kinked soon enough too and they'd have had to come up with an alternative so swapping out for a rigid pipe would have been a good option. We just beat them to it half a century later.