Mennekes 24198 is 32A 3 phase neutral and Earth.
Normally want the neutral when you want to power a 3 phase 415V item with a control system - you take one of the phases and neutral to get your 240V for the controls. (The similar 4 pin sockets don't have a neutral. Each of the individual phases in 3 phase 415V is only 240V to neutral)
It'd be relatively easy to just take a single phase and convert to a blue commando socket to "theoretically" get up to 7kW charging.
32A 415v Plug to 32A 230v Socket
Note, they describe the adaptor as "for testing".
(Presumably worried about unbalancing a three phase supply - how bad that is depends on whether the building 3 phase supply board is the same one supplying the single phase supplies for lighting and sockets inside - the fact that the neutral is there suggests they're prepared for some single phase loads on the system)
Would want to confirm that the building are OK with you only using a single phase load before going that route. It would very much depend on what their other loads are and whether the 3 phase supply is also feeding the single phase loads - (if you find somebody that knows that I'd be amazed).
If it were me, I'd probably make the cable but only charge at 13-16 A, so 3-4 kW.
Going 3 phase to get 11kW could get expensive, but it is definitely the better solution.