A bit of explanation. When you say "the reed layout is English", I presume that you mean each button sounds the same note in both directions, which is the case with the "English concertina". But the "English" is more significantly characterized by a particular layout of the buttons and notes, not just a single note per button. As others have noted, what you have is a Maccann duet, on which each button also sounds the same note in both bellows directions, but where the layout of buttons and notes is quite different from an English. There are even different kinds of "duets", with layouts of the buttons and notes that differ radically from each other.
Best not to buy another concertina until you learn more about the differences. But since your Kensington is on order, and if the wait isn't too long, I would suggest (as Geoff also suggested) that you work with your little Maccann. Even if it's not your ideal, it should give you practice with various aspects of playing that are shared by all concertinas and will (I hope) keep you from going stir crazy in the meantime. (Well, that worked for me : I found a cheap 20-button Italian anglo to keep me busy until I managed to get an English of my own, and it was enough, though it didn't convince me to switch to anglo as my main squeeze.
I played the Jeffries belonging to the Abingdon Morris Men for many (25) years so I do have some knowledge of Anglos! What I meant by "English" was the same note in and out.
I had heard the names "duet" and "McCann" mentioned but until now never saw one!
I shall restore this one as loving as possible and then see if I stand any chance of playing it !!