Okay, I've finally got round to looking at my Brommie...
That axle nut cover would appear to be completely superfluous: When folded, there is almost a thumb's (certainly more than a finger's) width between the nut and the chainstay, and no reasonable way that the two shall meet. The mudguard stay would have to pass through the chainring guard to do so. Furthermore, the end of the skewer sits flush with the outside of the nut, which is itself a smooth dome, and unlikely to do major damage to the paintwork anyway[1]. Probably different with a non-dynamo wheel and a Brompton chainset?
The only slop in the rear end that I can see is when the bike is lifted: The rear end drops and is caught by the latch after about 2mm. Place it back on the ground and the gap disappears. Obviously with the elastomer rotated to the latch disabled position, this doesn't happen and the rear end folds freely. With hindsight, this probably isn't what Jurek is referring to.
I know that rogerzilla hates the latch with a passion, but I find it makes carrying the unfolded bike up and down stairs substantially easier (saddle nose on shoulder and away you go). Since you can turn it on and off by rotating the elastomer, I see no reason not to have it available.
[1] It would have to get past my helicopter tape first.