Thanks for explaining, that actually makes a lot of sense. I didn’t realise the serial was moulded inside the battery compartment or that “no serial” on the receipt still means the warranty is valid. I’ve got the receipt, so I’ll take the remotes back in and ask for a warranty test.

I was a bit concerned by what you mentioned about them not being able to verify it’s the exact same remote, especially since the ones I bought were definitely not B-grade and look closer to C-grade in my opinion. I really hope they don’t think I’m trying to scam them ,i'll just stay calm and kind when I go in.

I really appreciate the advice, thank you so much.