You were not fined, methinks. A conditional discharge may not be combined with a fine. The Court of Appeal have ruled that it can't be [ R v Sanck 12 Cr.App.R (S) 155 C. A.] It can be combined with a compensation order or an order for costs and with some other orders e.g .disqualification from driving , but NOT a fine.
You can always check with the court if you want. Tell the insurers that you made a mistake and it was only a conditional discharge and costs of £40 and you therefore are reapplying to them . It's important that you make that clear because any other insurer you go to for this or anything else will ask whether you've ever had insurance refused, quite apart from asking about whether you have any convictions. You don't want to be answering ' yes' twice and/or endlessly explaining that you were refused because of your mistake.!