To wander back on topic re the signature: From Bills of Exchange Act (it's a different number in the Act in UK, Australia, Canada & New Zealand), but it's in ALL of them that I have checked:
Presumption of value and good faith:
(1) Every party whose signature appears on a bill is prima facie deemed to have become a party thereto for value.
So, if there's only one signature, then there's only one party there to for value.
Printed copy · Anthology Volume 1, page 239Printed copy from The Tender For Law Anthology, Volume 1, page 239 (printed 14 June 2014). Added by this site; not part of the Facebook export.