That's your take. Business' take is that they are more than willing to invest the time to find nuanced subtle differences between countries regulatory environments so that they can exploit them for monetary gain. The UK REACH and EU REACH regulations apply to production process - not to the finished exportable product. Hence TSMC in this case would only need to implement REACH within the country it has chosen as its production base. Between the choice of the UK or EU - this would mean it is still only "one thing" to take care of. Unless it ever intended to open production bases in both territories - in which case the territory with the "older" version of REACH would almost certainly win any "ease of doing business" test - so probably the UK at some future date once EU REACH Version 2 materialises (and assuming the UK doesn't blindly copy-paste it again).