Bike sizing question - are these two sizes actually that different? Could use some advice on bike sizing. I'm in the market for a new commuter and after a lot of research I ended up picking this one:
https://www.bergamont.com/gb/en/product/bergamont-vitess-n8-belt-gent#geometry

Unfortunately it's online only so couldn't try it and returns cost £35. I'm 6'0" (183cm) with 33" inseam (84cm). I ordered the large (56) frame but when I hopped on, the top bar was too high and couldn't rest comfortably when standing over it without strong pressure down there. 

I'm thinking of ordering the smaller one (52) but wanted to check with you if it's not too small (and avoid another £35 return). Comparing the two sizes - there doesn't seem to be much difference apart from the shorter stack/standover! The seat and head tube are slightly shorter (shorter stack) but the reach is the same. Does that mean that the smaller bike will fit just as well or am I missing something? 

Here's a comparison of the two frame sizes (you can see the comparison if you click 'Shadow bike'):
https://www.bikegeocalc.com/#9Bergamonta0b4c789.58314d280e624.25905f788.81524g993.29239h427.82039i340j340k1446.65227l926m1194.58314n765.75095o1251.33031p1005.28465q1272.29156r1404.18714s1006.29693t31.8u40v6w7.75408x10y280z40A0B150C25D458.77624E42F172.5G30H30Z6Berg+Ma0b4c791.02661d280e642.17724f752.08989g995.28771h435.49726i340j340k1443.36749l907m1198.02661n765.60378o1248.09764p986.28465q1275.73503r1391.63503s986.28465t31.8u40v6w7.75408x10y280z40A0B150C25D458.62011E42F172.5G30H30Z

Also full geometry is on the bike website: https://www.bergamont.com/gb/en/product/bergamont-vitess-n8-belt-gent#geometry

Thanks!
You'll get 40mm more stand-over clearance with the 52 over the 56.

As the reach is about the same on both sizes you will not be cramped by the frame, but I suspect the 52 may come with a shorter stem. You may need to buy a longer stem with a little more rise to get the effective (to the handlebar) stack and reach that you need.