Hi Connor,
My exhaust manifold was cracked and letting in diesel fumes through the cabin.
I emailed Honda UK and explained that having a 2 year old in a car with diesel fumes was a no-no and that I'd heard it was a common problem. (It wasn't a recall, they waited for customers to have the fault before replacing with a single manifold unit, as opposed to the original 2 piece manifold which cracks along the weld. Cheap way of keeping a reputation?)
Anyway, they replied agreeing it was not good, and even though my car was 8.5 years old (2006) and well out of the extended 7 year warranty for this, I should get in touch with local honda dealer.
I then forwarded this email to 2 local dealers who asked for car reg, my details etc, which I emailed them, and one dealer said not covered anymore by warranty, but I could pay £650 for replacement(!).
Fortunately, the other honda dealer (Ashford, Kent) told me they'd explained situation to honda uk and secured a replacement, at no cost to me!
Took it in for a day, got it done and all sorted.
(But now, a leaking injector is giving me that familiar diesel aroma again!)
If I were you, try a few local honda dealers after emailing head office first. Your avatar looks like you have a little one, use that as damn good reason to get sorted, but keep it nice but firm.
Good luck!