Higgs

These, again from Toolstation are very good. Prep Heavy Duty Scraper 100mm | Toolstation Have found this very satisfying, going through some layers of paint on a GRP boat. With care. Works much better, if the previous painter hadn't prep well.

Also found this to do the job. From Toolstation. I've been using this recently.

Jet-Rotary JR-100-EL Renovation Miller - AIRTEC The machine above takes some care to use, but it will cut through and get to the steel. Barring that, have about six stiff scrapers kept sharp. 2". Go right down to the steel and sweat. The sound effect should be like a well sharpened wood plane going through wood. I say six scrapers, because constantly sharpening will make the scraper shorter each time. Having six circulating will keep the scraper length reasonably long. Barring that. 60 grit on an orbital sander. Just work like a robot.