Hi
I have just put a genuine spoiler on my car and yes I believe it is a bit of a faf to change the light. I have attached a link to the fitting instructions of the spoiler. If you look at how you fit it it shows how to fit the light so maybe you could use this in reverse.
my advice is to buy a genuine light, I tried a cheap one on eBay and it was rubbish.
https://www.coxmotorparts.co.uk/wp-content/uploads/2017/08/08F02T1G6-.pdf