It's unclear, what the name "Triumph" inside the CPC-OS rom should mean. We suggest two possibilities:
There has been a typewriter manufacturer named Triumph, concerning the CPCs typewriter keyboard, this could have been a reasonable partnership - but that company fusioned with Adler long time ago, so for that partnership, the boot message should have been Triumph-Adler 64K Microcompter. Actually, the typewriter relation isn't too unlikely. The brand name Triumph-Adler (TA) has been used to produce various computer hardware from 1971 up to today, spanning a range of electronic typewriters, alphatronic computers, and laser printers. More info on the company history is found on their webpage http://www.triumph-adler.de/ (german)
There is also an Triumph Electronics company in USA, though according to their About Us page, Triumph Electronics incorporated in 2007 (thus it can't have anything to do with the CPC), interstingly, they say We stand out from the crowd by our professionalism (though as by 2010, the About Us page still doesn't work yet with Opera, nor mainstream browsers like Firefox or Internet Explorer).
See http://en.wikipedia.org/wiki/Triumph for more possible meanings.