Ok, well, first of all, I don't really know what the royal society for the blind do, so I think most of my confusion stems from that.
Following that chain of thought, I don't understand why the royal society of the blind would deliver a tandem bike to anybody, let alone you, as I don't know how this organisation relates to you.
Also, wouldn't blind people riding bikes be a bad idea, compounded further by two blind people riding the same bike?
Lastly, I just want to stress I don't mean any offence by any of this, I was just genuinly confused ny your post, and you asked.