Hi Graeme,
Thanks for the advice. I have used CISS systems on Epson printers before but have struggled with quality. I might well have another go as its been a few years!
I had a similar problem recently with an Epson R3000, it was auto cleaning far too much. After a search on the net I found that updating the driver was the solution. As this is the first Canon printer I have used for some years, it could just be a Canon thing which I am unfamiliar with. I don't like to waste the ink, but the frequency is a pain in the rear as much as anything else.
I will have a look at the link. Thanks again.
Steve.