I want to attend a conference in November. I applied for a UK visa but was denied because I didn't declare a criminal conviction of 1989. There was no jail term, but I was given 50 hours of community service and a fine of GBP230. As at the time of my application I couldn't remember in details the verdict, I didn't declare it. Besides it occurred way back in 1989. I decided to apply for a UK Police record, which I have now.
I need an honest opinion on what to say about not declaring it or perhaps a better way to approach this.