They certainly have access to a database so maybe asking first is a cross check and test of your honesty. If you'd been in a significant and/or at fault accident in last two years it's reasonable to expect you to have clear recall. If it's four and a half years ago for minor scrape then they'll give more latitude.

The database(s) is/are pretty comprehensive and go beyond actual claims for insured and named drivers. As an example I had my daughter, then 23, on my insurance when seeking renewal quotes in Jan 2016. When checking history they could link her to a claim in April 2014. She'd certainly not been involved in anything - was car less and in final year at Uni in Sheffield. After a bit of head scratching we concluded incident involved her boyfriend who'd scraped a housemates car outside his University digs in Southampton. She was a named driver on his policy.

I contacted the ICO, but all they could tell me was to contact my insurers for the information. Not tremendously helpful but it doesn't sound like their specialist area - they just deal with legislation governing access to personal information.