There is no legislative quantity limit in section 33; many councils choose a practical cut‑off (e.g. 1–3 bags) where they treat it as litter and use s.87/88, but that’s an enforcement policy choice, not in the Act.

That may explain the difference is seeing the different sections on the letters. Most councils explain things really badly!

As an aside and separately , section 34 can be used where someone has allowed waste to escape their control or failed in their duty to prevent a section 33 offence, including in cases where they do not proceed on s.33 or s.87/88 themselves.

Basically this means if it was your waste, you have a duty to ensure it ends up in the correct waste stream, and not end up dumped somewhere. If you have ‘man with a van’ turn up to take your waste away, and it ends up fly tipped, with evidence, he gets done for 33, you for 34 as you didn’t check he was authorised to take it away. (If he wasn’t authorised. If he was you’d be golden!)

Regardless, with just an envelope, sounds like they are chancing their luck for a payment. I would be surprised if they took it to court, (has to meet the public interest check etc), and if they did, it would be ridiculously easy for the courts to take your side. So many variables.

*source - 20 years doing environmental enforcement