
The downlights in my lounge area are labelled EDI Light, Austria. 12V 2.5W, and in the bed area they are labelled Dimatec, again 12V 2.5W but these are dimmable - although controlled via a switch and not a dimmer.
I suspect Dometic's lighting products are now sold under the Dimatec brand.
As Colin mentioned above, these downlights are fairly generic and if I were you I'd change all four so they match lumens
and colour temperature.
Jacksons Leisure,
https://www.jacksonsleisure.com/ sell the Dimatec range of downlights.