well the seat clamp is not the 'Dutch" style that I was guessing: it has a slot for a bolt with a "cleat" to fit in it. Chances are good that it's a Dutch or British frame and maybe 531 (at least the main tubes) or something like it. Stamped track ends are not uncommon even on good quality frames of that vintage, so it's not necessarily a low-end or even mid-level frame. I'd think anything from Raleigh/Carlton/Gazelle or another big brand would have a serial number on the BB shell, so this might be from a smaller shop.