I've tried marlow in both d and e width (and other close friend us EE too)
D width is surely narrower than uk e.
E width is very similar to uk e, maybe a touch wider.
My experience is one full size down too, ex. Us9/uk8
I perfectly understand your disappointment but imho returning a pair of shoes only because they're slightly creased, the same creases you will get at the first wear is a waste of time and money.Better to ask for a discount or a gift (free shoetrees ?)
You are comparing a brand who make one/two pair of shoes from an hide, with a brand which use even the last millimeter of those expensive leather.
Obviusly JL select the denser and better part of the hide for his vamps, with Meermin is only a matter of luck, some pair can be perfect, others very poor.
Anyway the creases on your Meermin are perfectly acceptable.