(2-part post):
While the detailed records of court cases are not available to the public, every court has a 'register' (which is a public document) which records the 'bare bones' of each case. (e.g. "On the 4th July, 2007, Fred Bloggs was found guilty of ...... and sentenced to . . . .".
So, theoretically, you could consult the register to see what fines have been imposed. However, given that the legislation only came into force in February, and court action can't be initiated until after the 14 day period for payment of a fixed penalty of �75, it would seem likely that there have been very few court cases before yours.
Additionally, when imposing fines, magistrates take a person's disposable income into account. So, the actual fine imposed on somebody else might not be the same as you might receive.
The maximum fine is �1000. It's extremely unlikely that a court would impose a fine anywhere near to that level but, for offences which could be dealt with by a fixed penalty, magistrates normally seek to impose a fine greater than the fixed penalty (�75). Without knowing the exact circumstances (or your income) it's hard to be precise but I'd guess at a fine of roughly �100, possibly plus about �20 to �30 for court costs.