Application for naturalisation issue

m about to apply for naturalisation

I'm concerned about my good character section

I'm EEA citizen.
In 2002 I came to UK before my country joins EU, I believe that was on a tourist visa but work for 2 weeks, my home was raided by home office. Transported to police station and to the detention center by Heathrow for one night.
Never been in court, and there wasn’t a case.
I left UK.

Come back in 2007 and live since then.

I'm wondering do I have to declare this in my application if no
what date I should put in an application , under first arrival to UK.

Considering that was 15 years ago< is it any chance to check it ex. Freedom of information .or home office before applying for British naturalisation.

Many thanks Chris