Let's prey to the GPU gods then.The are sanded down, polished and remarked 2011 garbage. So you can just as well reflow the existing GPU. Or just don't do anything at all. I got rumor new chips will be arriving in the next 2 weeks.
Just as an update to these chips with even traces of thermal paste still on them, I bought them from eBay from laptop_mb_seller which turns out is L2Computer inc. It's only £400 but still. \
Anyone ever reading this that is noobier than me, stay away from Laptop_mb_seller / L2.