Hanimex 400mm f6.3 M42 not preset - who made it?

[nickant44]

Hello all,
I'm a big fan of using old telephoto lenses, especially for moon shots and wildlife, attached to my Canon 40D.
Last weekend I picked up this lens at a local market.
It is not the thin, long-tube preset type, but an automatic, with what appears to be 7 elements.
An old magazine (1979) lists the specs correctly for dimensions but says 4 elements in 3 groups.
It weighs 1150g and is 255mm long and uses 67mm filters and is made in Japan.
It doesn't look like the TX type Tokina lens here: http://forums.steves-digicams.com/pentax-lenses/158845-vivitar-400mm-f6-3-modification.html and its serial number may be for Hoya or Makinon??
Some initial shots show it to be very sharp.
Apologies for the blurry first photo; it has a bit of dust not fungus in the second photo.
Any ideas as to its origin?

[nickant44]

Only shows correctly if I post a second entry.