Hi guys,
Just thought i'd make a note here for future reference as I had the same question when I was looking into the Canon cashback.
The canon cashback website states payment will be made within 30 days of receiving the claim, in my case it has taken 25 days so while the website states within 30 days it seems payment is made later as oppose to earlier so beware of having funds tied up for nearly a month.
Yea, from past experience, it does take close to the 30 days to get the cash back through. Never had any problems getting them processed however, so it's reliable, but slow.