Where did you find the name Crissworth?
I'm finding a lot of variations on Cosworth on FamilySearch that are in Cornwall. In fact searching on Crissworth as a first name doesn't have any results at all. Crissworth as a surname has no results as well, although there are a lot of variations on the name Coswurth.
http://www.freebmd.org.uk has no Martin's registered with the name Crissworth in Nottinghamshire. There are fair number of William Martin's registered in Nottinghamshire in the 1890-1900 time frame and one William Cheetham Martin in 1890 but no "William C" Martin. Any of those William's could be him.
I just google'd Crissworth and found a Cressworth (or Crissworth) Robert Cadden on the NSW probate site at http://search.records.nsw.gov.au/items/787677;jsessionid=D3CCB7995EA3BFE22794D76739BFC6AA . Not a Martin, but still interesting.
Could his name be Cressworth?
Another Google hit on Crissworth produces an article in a Saudi newspaper on a Martin Crissworth who is a dentistry professor in Canada.
There are 2 Crissworth's on the http://www.naa.gov.au site. One is the previously mentioned Crissworth Robert Cadden and the other is Betty Ann Martin whose next-of-kin is your Crissworth Martin.
FindMyPast.co.uk was similarly unhelpful and the only results for the name Crissworth on Ancestry belong to Crissworth Martin and his family. I have the feeling that early in his life his first name changed to Crissworth from something else.
Your first step should probably be to purchase his marriage certificate from NSW BDM at http://www.bdm.nsw.gov.au/bdm_fh.html . They're expensive but I think there are transcription agents who do this and you could find his parents there.
