Got reported for possibly undertaking?

I was driving on this dual carriageway (national speed limit). I was on the right lane and a guy was hogging the right lane driving 55-60mph so I flashed him so he can go left (there was so much space) but he refused to do so. I switched to the left lane and overtook him but as I turn back to the right as I was overtaking another car he sped up intentionally which made him really close to me when I was turning to the right lane.

The police need all my details including insurance and they are asking for my side of the story (they didnt even tell me if this was the incident so I am just guessing)

My question is based on what I have described what penalty could I possibly get or could they just simply ignore the incident. Could I ever be possibly prosecuted for Dangerous driving with a DD40?

Please let me know I am very stressed out about it. Only reason i was rushing that day is because it was my engagement day and didn’t want to be late. Please note that i have been driving for 4 years and never had even a parking ticket. So my record is very clean.