Charlie;
I don't think there are any design or construction, or pressure factors which require the switch block to be in any particular position or attitude, so the position you find it in, especially with a retrofitted one, is strictly how the plumbing worked out when the installer located it...having said that, he didn't make it any easier to inspect by mounting it "upsidedown"...as 133 notes, Shuttle "should" self-recentralize as it has springs on either side, but may/typically needs a bit of energy/persuasion to "unstick" and encourage this...try jabbing, sharp risetime inputs on the Brake Pedal (I don't believe I'm saying this, but some additional shock energy ("Lucasfix"!) inputs in the form of light tappy-tappys with a soft hammer while a helper is applying the Pedal energy inputs, may be the trick)...
...BUT FIRST: Remove the Switch from the block! Having moved from the central position, and extended the plunger during bleeding is not when the plastic peg gets damaged/pieces sheared off, but when returning it and compressing it with not much of a ramp on the Shuttle IS...see also:
https://www.sw-em.com/Two_Wrongs_Mak...g_Valve_Switch
...so how would you know if your Pedal jabbing inputs have recentralized the Shuttle, when the Switch is not preset to allow this to be indicated electrically?... AND the installer having made it not particularly easy for you by installing it upsidedown and maybe in a precarious position for checking, and you don't have a borescope handy?
...I'd suggest checking in a similar way the Switch itself does!...how about checking how far a wooden or plastic (non-damaging!) "depthprobe" (standin for the Switch plunger), is able to be inserted,
before the shock inputs, hopefully these will persuade it to move, and the
after checks will show a bit less of insertion (I only expect a 1/8 to 3/16" difference, so measure carefully!)...all this, and I hope the internal seals of the Switchblock don't let you down and there is excessive leakage out the Switch port...
Good Hunting!