Without wanting to confuse matters further, I'll just add my input. Same as what Dave has said really, in that you're more than likely going to receive a letter from C2C at some point in the near future, and it'll probably say that they intend to proceed to prosecute you under s.5(3)a Regulation of Railways Act 1889 (RRA), which carries a maximum sentence of £1,000 fine and/or 3-months imprisonment (the latter is only enforceable on subsequent breaches of the same offence). Realistically though, you could have a string of previous convictions for the same offence but will never see the inside of a prison cell, purely because there isn't enough room. Likewise, unless you're very welthy, very persistant or both, a £1,000 fine will be very unlikely. Courts tend to use a week's average salary for RRA offence fines, means permitting (£350), and half of that (£175) for railway Byelaw offences. As you're a student, and depending on what you tell the courts you can afford to pay, you could look at a fine of a lot less than £350. Bear in mind though that the TOC's costs will be added to this, as will the compensation (fare owed) and victim surcharge (£15 that goes to Victims of Crime charity).
Could amount to an expensive day out, and I'd urge anybody to try to avoid court where possible. A lot of TOCs have a policy that for first offences they'll offer an administrative settlement by way as a final warning, with no further action taking place. This usually means about £100 to £200 for the offender, but no prospect of court or a criminal record! They usually take in to account the cost of the fare avoided, and possibly previous warnings (Penalty Fares, UFNs etc). I would suggest you write to the TOC when you receive their correspondence, and offer to pay all their reasonable costs so as to keep the matter from going to court, and apologise profusely! They by no means have to accept, and can still go to court, but it's worth a try for the cost of postage!
Good Luck.