Indeed..
...Or, sure.. just get a 'Stanwax boardie'..
..But, point-being, you *can* 'DIY-it', it's not that hard.. See note, top-left, about adding a 'second SSR for Mech shutter'.. Of course, you would only-use +12V DC to 'drive' the Ledex shown in this thread,
(..not this 24V, unless you expressly use a 24V coil-one..), but.. you can still 'gate' off this circuit.. Note, too, that this does not detail a 'keysw lockout' for the shutter, but, as you say, 'trivial engineering'..
..Perhaps when I get some time in 2019
I can draw-up that as a 'DIY-diag', also.. Will-post, if/when..
j