My fitter is good but Melbourne based. I wore an underwire bra with a soft pad for 12 months until I got a prosthesis fitted (seroma made fitting accurately impossible till it was gone). I never had the slightest trouble with an underwire bra - the soft pad moved more than I liked but that was at least understandable. A prosthesis should sit snugly in the bra pocket for that purpose and not move around. I was wedded to an underwire bra for support but my fitter came up with a no-wire bra that does the job every bit as well.