Hi, it looks to me that it's simply a mis-printed 0, it looks much more 'closed' than the normal Cs./ Also, this would fit with the serial formatting.
Here is a quote from a post I made a couple of months ago when I bought a Randonneur with a funny serial:
Hi, from the research I've carried out, there is no single resource regarding Raleigh serials after around 1982 (besides American serials).
After reading on different forums, I spotted a few people had posted their serials of later Raleighs;
One guy had a 1991 with a serial starting with B
Another had a 1992 with a serial starting with C
Another had a 1997 with a serial starting with H.
I can only infer from this that the later Raleigh serials are as follows:
Axxxx = 1990
Bxxxx = 1991
Cxxxx = 1992
Dxxxx = 1993
Exxxx = 1994
Fxxxx = 1995
Gxxxx = 1996
Hxxxx = 1997
I have no evidence of what happens after 1997, they may indeed follow the same pattern or change altogether.
The digits following the letter (there are 4 on mine, may be more/less on others) I can only guess are the individual unit number. The second letter may indicate the builder of the bike (especially bikes that were built by the Special Products Division) or any number of other things.
I hope this will be helpful; I'm not 100% on it but I know of 3 other bikes that follow this pattern
Edit: My serial was EO 5283, so again this would fit with the idea that the first 'C' is in fact a 0