dewal cordless drill?

It says place a hex key in the chuck strike anti clockwise to release the chuck.
I can't two grip segments came out of chuck as normal one b...r stayed down so I could not access the screw. I cut the chuck in half with an angle grinder enough to get at the screw and loosen. Tried with pipe wrench to remove the chuck but it doesn't seem to want to budge. Any suggestions would handy if they result in chuck removal. new drill over £100 . Many thanks.