Since this thread started I've started (sadly) looking at the safety aisles in the DIY stores - some stock PED approved EN3 kitemarked Gloria products under the Kidde banner, others still stock direct import First Alert products that are not PED approved and have US pictograms, fire classes & ratings.
Although being UL approved I would be confident about their efficacy, unlike the chinese powders appearing in some discont supermarket chains that have a PED CE mark, but thats about it for testing and approvals.
The main problem is the use of 'domestic' extinguishers in workplaces. The RRO guide now accepts them for small premises, but only if the expiry date is complied with. Now from a cost point of view it is cheaper to buy a factory sealed 2 kilo powder and replace it every 5 years than by a standard refillable and have a basic service every year and an extended every 5 years, but to most an extinguisher is an extinguisher so instead of the EN3 kitemarked factory sealed 2 kilo ABC Powder with guage, several places go for the gaugeless non compliant 600g BC powder that won't work on one of the main fuel classes present (A).
Ironically people did used to have proper sized extinguishers in the home - Minimax & Merryweather targeted the home market with 10 pint & 2 gallon extinguishers sucessfully in the first half of the 20th century, even making them in different finishes to complement decor - & many private cars had a Pyrene extinguisher under the hood. The birth of the aerosol can led to the smaller extinguishers now seen with as little as 500g of agent