Not sure if this has been recommended as havent read all the posts....
Try Cuplex -we fab it brilliant. The only thing that worked after a 3yr veruccae - we tried leaving it, cuting it off(recommended by doc), bazuka , seal and heal and this was the only thing that worked and has been recommended by friends too. It costs about £6 and you HAVE to do it EVERY morning and night, but it really does work.