The more detailed UK specific warning direct from TYCO UK the importer (Express are TYCO's appointed distribution agent, but TOTAL is a TYCO company) clearly states that all UK TOTAL extinguishers may be affected - very few TOTAL items are sold as 'Flamefast', most are sold as TOTAL via Express Fire and the supplier adds their own company label, so don't be mislead by the Neuruppin letter.
I copied my text from the far more comprehensive TYCO document that includes photos & pictures of the two types of factory labelling & the extinguishers - both the more common TOTAL and less common Flamefast ones.
Stamping is normally on the face of part of the brass valve - it will include the year of manufacture and the CE mark, plus other numbers such as batch number, etc - this is where the 231 would be.
Again check anything TOTAL!
(Ironically TYCO, although owning TOTAL, don't use their extinguishers in the UK, instead briefly used Excelsius and more recently Firemark!)