There's a slight bit of gear lash when rotating the cranks on my SL and also on mrs levity's, but nothing I'd describe as "sideways play". As @Fivetones suggested you should cross-post this in the SL Owners thread.
I put it up as a separate thread so as not to get lost in all the what mudguard, spring, how much does it weigh etc talk. I think this could be a real issue!
Not very good with computer tech, if you grab hold of Crank on motor end and pull and push it there is about 1-1.5 mm movement, like on a normal bottom bracket before you preload the bearings.
I gave mine a wiggle when passing it in the garage a minute ago.
I pulled my crank too and forth near the bottom bracket with significant force, but have absolutely no play whatsoever in mine.
I can only assume this is what you’re referring to since you can’t post an example?
I probably only have ~100 miles on mine so far though.
Popped round to Bicycle Chain W-s-m earlier and spoke to one of the guys from behind glass, he said Spesh say 1-1.5mm play is fine any more and its an issue apparently they have had one failure in the shop so far.