Alba, it's not so much that I care who makes Slazenger bats - I don't, and I've had a number of good ones. It's that with every manufacturer of bats we are asking the same questions over and over, and there seems to be little to no insight.
This forum is very rare in that it tends to the end of the scale where people buy bats and don't use them very much, then sell them. In the real world, people buy a bat and use it till it breaks or dies, then buy another. Every net/match I've ever been to, the only bag with as many bats in it as mine is usually the team bag...
While we care about the provenance of a bat, for better or worse, because we think it is the indicator of whether it is any good, the reality is that for UK made bats there are perhaps fewer than half a dozen makers manufacturing cricket bats in bulk in the UK for theirs and other brands. You can probably name them, and it's no secret. It's commercially up to them and the brand whether they allow their name to be used in marketing.
We've done this subject to death many times, and the reality is, if it makes commercial sense, there is nothing wrong with it. If a brand tells you it is made in the UK, and it is, that's fine. If a brand lies, it's not. You should buy a UK made bat on a bat shape that you like at a price point you want to pay and feel assured that even if it is made by one of these "outsourcers", they all make exceptional cricket bats.
If you want something that isn't UK made, you know where to go for those too. And once again, the quality is generally as good as the UK made bats.
On Buzz's point, it's down to the commercials agreed between the two parties. If the manufacturer incorporates a clause as part of the deal that affects the purchase price of the bats then where's the problem? It's basically paying less cash up front by paying with IP, and happens a lot in many sectors of industry.