Hi Rob,
The "wesellclassics" Hesketh is local to you, owned by a club member who has regularly used it for many years, so it's a good EN10 Hesketh. Needs cleaning, but that's easy and it does come with a full stainless steel exhaust system, still in the box.
The Bonhams hesketh does not show a reg number or frame/engine number, so I can't help with that one.
Best regards
Dave H