I fitted a Marathon Plus to the rear wheel of my Brompton. Took at least half an hour and lots of swearing. There is no way I could have fitted that tyre with hands only and after cycling for 70 plus years I am not a novice.
I don't have Marathon Plus for Brompton, but I have one for 20" and, in fact, I was putting it on on Sunday. It was a few minutes with hands alone and this nor for show but just as the simplest way to get from A to B.