[7s26b]

I think you'll find there is a crown 60E31NS1, crown and stem gasket 0A0150B0A, stem 0351161 (a fairly standard assembly). But inside the crown tube is a plastic insert (HOLDING RING FOR CROWN GASKET 89995390), this is the same as many of the smaller 150m quartz Seikos.
Here's a picture taken from http://forums.watchuseek.com/f6/seiko-7546-604a-plastic-crown-tube-insert-replacement-901779.html
I hope this helps.

 

[7s26b]

Here are some crappy pics from ebay http://www.ebay.com.au/itm/Vintage-Seiko-Arnie-or-Arnold-Diver-Watch-H601-parts-Case-Shroud-Etc-/221242987521?nma=true&si=TGjii7dScIDB04Dro8MaKZBZKHc%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
If you take the time to cross reference the holding ring for crown gasket and the H601, there are over 500 candidates !! http://service.seiko.com.au/pls/apex/f?p=104:20:80020624100368:Go:NO:RP::

 

[7s26b]

perfect - thank you
this is what I have , I'm hoping it will suffice

Do you have the part number for that crown??

 

[7s26b]

60E13N or 60E15N

OK, so that's a 4205 diver's crown - which has a double seal ( an extra one inside the crown).
It may well work, but I don't think it's designed to be used with the plastic tube insert ?. I've had a look through some of the watches with the same plastic tube part number and a 6mm crown. The STM005 crown looks like a possibility and is available 1E60D0SNW1- and there are others.

http://service.seiko.com.au/pls/apex/f?p=104:20:3520683964027471:Go:NO:RP::