thanks for the help
yes its not anodising its like a plastic ( vinyl ? ) layer over the aluminium as if it has been sign-written and then melted on? i can find a seam in this layer.
i thought paint stripper - as i have also used it before on a similar frame - to begin but will it eat through the plastic-y layer easily enough?? or will i spend hours and hours scraping and srcatching at it? thanks for your help