So was it still called Debonair or did they call it a CRS Century? If they did then I'm sorry we've made you waste a good puzzle grobmotorix!
I've been looking around, but haven't come up with anything concrete.
The main online resource on Ford specials gives CRS Auto Engineers as selling two chassis from 1961 on, the Conquest for Ford E93A mechanicals, and the Century for more powerful engines. It also notes that they started to stock a range of fibreglass body shells from manufacturers including EB (Edwards Brothers).
The entry for CRS in Georgano's 1968
Encylopedia (below) specifically mentions the Debonair body, but unfortunately doesn't give any model names.
I just can't decipher the last letter of the registration number, though I agree with Carnut that it looks like 2 RK<something>. I've tried a few combinations, but nothing's come up. But then it's the sort of number which could have been subsequently sold as a personal plate. Even if we can confirm the correct number, it's quite likely to have been reallocated.
So not much further on, really.