From N Gauge wiki
Ultima Models was a manufacturer and supplier of N gauge kits (1:148 and 1:152 scale) including the former Cav'n'dish range.
Ultima Models was founded by Colin Allbright in 1983 and grew to include a wide range of rolling stock and detailing parts acquiring the former Cav'n'dish range and other products along the way. Ultima gradually ran down in the early 2000s after Colin Allbright joined Bachmann.
The range was purchased and relaunched by Etched Pixels