It appears to be an attempt by ColoVantage Screening Service to get more business from people after possibly waning interest/participation??.
The BowelCare project was started by Rotary Club of East Gosford Inc and now encompasses Rotary Districts 9710 and part of 9675 as well, in 2018 it will run from 1st April 2018 to 31st May 2018 and kits will cost $15. This price covers pathology testing and notification of results to both the participant and their nominated Doctor , an obvious difference to the $21.50 in the letter .
CancerCare Australia came out of the same beginnings, which was called Bowelscan, and became a standalone charity that "covers 110 Rotary clubs and over 700 participating pharmacies across Greater Metropolitan Sydney, Blue Mountains, Central Coast, South East New South Wales and the Australian Capital Territory". It has (copied from it's website) "expanded its focus to now support cancer related programs such as the Shirley Shuttle, Cancer Council Bus, Cancer Council Home Care and sponsors the Carols by Candlelight Mt Penang utilising the profits from the sale of the BowelCare kits."
The Australian Govt through the Medicare system provides a completely free Faecal Occult Blood (FOB) test service once a person reaches 50 years of age. This test is expanding from every 5 years to the recommended every 2 years until you are over 74 and the 2 yearly test is going to be completely phased in by 2020. The company that provides the pathology services has changed from Specialist Diagnostic Services (operating as Dorevitch Pathology) to Sonic Healthcare Limited (Sonic), but the register of results is held in the Govt database.
To read more about the free Govt service the link is to the home page:
I understand using a paid for service if you are under 50 as the free Govt one is only for those 50 and over, but also take into account that FOBT kit results are only about 30% correct/accurate and the real recommended rate is once per year for testing. Reasons for incorrect results can be anal bleeding (from a number of causes not related to cancer eg hemorrhoids) which will result in false positives. Not all cancers bleed until too late or at all, some may not bleed during your test period and these are false negatives. Doctors can also give you a referral to a pathology service to have this test done, it may be free or it may cost depending on a number of factors.
The best test is a colonoscopy and you can get a referral from your doctor to be tested, however this test may require payment by whomever performs the procedure.