The fee presumably is for Royal Mail collecting it on behalf of customs. Or is £8 + £8, RM have always charged £8 to collect it, no matter how much customs charge there is and they are entirely different things - I have no idea if that is the case after Brexit.
There is already a customs/UK thread going - may be useful to keep it in 1 place if we can ( you probably didn’t know) :) LINK HERE
If you bought it PRE Brexit - you should not have this fee anyway so far as we can acess, but one thing I will tell you because i fought a charge last year - is that you can fight for incorrectly charged duty, but you can’t reclaim the £8 collection fee - I was told on the phone by customs you could, but on the letter i eventually got it said not. Again, post Brexit I have no idea.
here is my mammoth fight for wrongly paid duty thread - HERE I understand some may think it petty - I however see it as what is ‘right’ and ‘wrong’ and wanted to prove a point. Again this process/values and so on may well have changed.
You also have to remember that before, it was a ‘lottery’ if you got charged or not, you were either lucky or not (90% lucky I’d say) - and the Chinese found ingenious ways to bypass it for us (sneaking it through Europe etc) and I have every confidence they will find another way again, they just need time lol!
It is important to remember that if the light is showing a ‘discount ’ of say 40% when you buy, that is irrelevant because the sender is legally bound to write the FULL price on it (even if they don’t) this is a definite when buying from the USA pre brexit.
If you can prove you bought it pre Brexit you should be able to reclaim the customs fee , because then there was no charge for anything under £15.
I wonder could you let us know in more detail - which light (web page) and what date you ordered and if it is a customs charge, or a RM fee for collecting. 