The obverse is a bit clearer now. I can see the eyes of a crude portrait and maybe a crown, but that's about it. 17mm is definitelty on the small side for a typical English short cross (which it obviously isn't), long cross or Edward Penny, but as I said I don't think it's English anyway.
Maybe it's a continental sterling imitation, but I can't find any that look like that. The fact is I really don't know.