This was the first tandem I lusted over 30 years ago.
I tried to order one, but after waiting a year it never showed up and communicating with Mercian at the time was difficult. I did end up buying a Mercian road bike which I enjoyed a lot and regretted selling it. Its amazing how short the bottom boom tube looks.
Mercian built some great road bikes, but not many tandems.
Have only seen a couple of them; their reputation for tandems was not the best, there were many more Jack Taylors around in the US at that time.