Is there a 3 position key switch spring return available in the 56 series?
No, unfortunately there is no 3 position key switch spring return in the 56 series. However, you can make one up with the following parts:
56E1-GY- Standard 56 series enclosure 56L1/22-GY- 56 series front cover with 22mm hole for key switch ZB5AG7- 3 position Key switch spring return ZB5A210103- pushbutton and selector switch body (2 normally open contacts)
Be mindful this would need to be constructed on site, unless you make quote request which would then have to go through specials.