iPad AirPrint (iOS 8.3)

I have a wireless printer (Canon MG6450) which claims to be AirPrint-compatible.

It works o.k. from my Windows laptop, and used to work from iPhones and iPads.

The iOS devices are now saying "Looking for printers... No AirPrint Printers Found" and won't print.

Is this a new feature of iOS 8.3 ?

A quick browse around the community reminded me of the re-boot option.

If in doubt, try powering off and on again!

The Canon software assures me the firmware is all up-to-date.

Re-booting the iPad immediately made the printer visible to it - but it disappeared after a day or so. Re-booting worked again, but that cannot be the proper long-term solution if I have to do it every day.

The problem has only appeared since devices were updated to iOS 8.3; could that be significant?

The iPhones now sees the printer without needing any re-boot, although it has the same standard of iOS as the iPad.

What should I be doing to use the WiFi printer properly?