Associate
If you're not wanting to ignore, sounds like you shouldn't, then send a letter and any evidence explaining the circumstances and ask for the ticket and fine to be waved. If they refuse, take them to court, the judges are human and I'm sure will understand your argument if it is as you have described.
Just done this with UKCPS (not as far as court stage). Lost permit for work, left note, went in to office to get temp pass, UKCPS ticketed me in the 5 minutes I was inside before putting the temp pass in my car! They rejected my appeal, so I took them to ombudsman and they found against UKCPS and order them to quash the ticket. I _would_ have gone to court if they'd pushed the stupidity of their original ticket.