There are about 5 medieval / late medieval bows reportedly knocking around the UK, held in stately homes usually. I don't know of anybody who's seen them, and I've tried many times to get in contact with the people who apparently own them to no avail.
This one sounds suspect, purely due to the woods used. Hickory would be a backing wood, making yew and wych elm the core and belly woods - which doesn't really make sense. Yew is a fantastic belly wood but putting elm in a core is pointless. Yew is often used as a core wood, but elm isn't exactly the ideal belly wood either. It sounds like the ultimate bow designed by somebody who knows what timbers are USUALLY used for bows but has no understanding of how specific timbers work.