Thank you for the advice I managed to get a puller kit and after hours of pulling and pulling and pulling and more pulling I got the majority of the dent out there is still a crease line but minimal filler is better than slapping loads on
This was how the underside looked
some light sanding
And a tickle of primer!!
Still a work in progress will post the finished tank in due course.
I like to sale a XT 550 cylinder!
The item is good condition.With piston,but the piston not is so fain.
If someone need I send to he details with photo.
Steve