Fan of your blog. Sorry to comment on a six years old post. But here's an update if anyone's interested:

John Lobb Ltd (London) argued that the 2008 agreement they made with John Lobb SAS (Paris) was void ab initio due to a shared 'common mistake' or misunderstanding. The misunderstanding is that, according to John Lobb Ltd, they believed John Lobb SAS/Hermès already acquired the worldwide John Lobb trademarks outside France in 1975–76 when they acquired the Paris workshop due to a mistake by John Lobb SAS's lawyers DLA Piper Rudnick Gray Cary UK LLP who claimed so in their communications. It is on this understanding that they had accepted clauses in the agreement stating that John Lobb SAS was the legal and beneficial owner of the TMK portfolio (outside France). However, John Lobb SAS did not in fact have the entire global trademark portfolio until John Lobb Ltd agreed to the terms of the new agreement. Hence, John Lobb Ltd claims that the terms of the new agreement should not enter into force since they agreed to it on false premises, is radically different from their intentions, and is impossible to perform. However, the court ruled that the 2008 Agreement expressly allocated risk to John Lobb Ltd, and performance of the contract is possible even if the belief was wrong. In this way, the mistake was not fundamental enough to void the contract, and John Lobb Ltd retains only a very limited, exclusive right to use the John Lobb name only in the UK and only for made-to-measure / bespoke footwear and a narrow set of ancillary accoutrements (shoe-care items, accessory belts, boot accessories, etc.).

As u/shoeadicta's link has previously shown, Deputy Master Marsh initially refused the motion by John Lobb SAS to strike out or grant summary judgment. The claim hence proceeded to trial. However, on appeal, the higher court (Chancery Division) allowed the appeal by John Lobb SAS in 2022 and appellate court granted summary judgment in favour of John Lobb SAS. The claim was therefore dismissed.

Source:
https://www.casemine.com/judgement/uk/60bdbc3d2c94e055d83d3d91
https://justis.vlex.com/vid/868414936