Porshe had some bikes as well. (wheels are carbon but weight more than mid range normal wheels)
I don`t think many shops would buy it as a part ex, You could try some BMW dealers, if its a mint condition than they might want to buy it for display.
But I would go eBay and list it in bikes and cars.
My neighbor had a BMW full susser to match his 540 BM and his BM enduro paris dakar something 🙂 People with money to burn can buy it, he probably would… as long as the colour matches his new M6.
And as it was mentioned value when selling is one thing but how much someone will pay for it is the other.
You can also try Cash Converters/Generator kind of places BUT it would be better to just keep it than give it away for £750-1000 or even less 🙂