Hi, the flower buds on Camellia are set in late summer/autumn, and need lots of moisture at that time, it could also need to be repotted into a larger pot, or preferably into the ground, [ I presume you're growing it in a pot because your soil isn't acid by nature] you can still use ericaceous feed, or even dilute acetic acid to alter the p h, and your plant will be much happier when it can send its roots down, Derek.

Could have been a early warm spell then a sudden steep drop in temperature for a few days followed by another warmup. This could disrupt the flowering cycle.

Thanks Loosestrife. I assumed it had to be weather conditions. Doesn't this climate change play havoc with our plants? Not much we can do though except keep to keep checking them for distress etc.