Cabbages Flowering... why?

My Pak Choi have, its due to the daft weather we have been having.

Are they still edible do you know? Should I try remove the flowers? Should I begin harvesting early because of this?

Sorry for so many questions

Sounds like your cabbages have bolted
1 what variety/type are they
2 when were they sown/planted
3 what are they planted in (containers/type of ground)
4 if you put your location in your profile it would help grapes give you advice
5 welcome to the vine.

6 The chooks luuuuuuuurve bolted brassicas!

Brassicas are cold weather plants, rather more suited to the climate of Dickens' Little Ice Age period rather than the halcyon subtropical heat we get now.
As a result, whenever stressed, like many plants, they are inclined to think, "Ooh, I'm done for, let's make babies !" and start blossoming.
Some varieties of plant are more prone to doing it than others; some will do it if planted at the wrong time (eg Chinese cabbage which are not really brassicas, if planted before midsummer, will bolt as the days shorten), if planted without firming the soil, crowded into containers, deprived of water, or any one of a dozen different reasons. Many of these even the more experienced growers can only guess at.
Personally I am inclined to harvest the leaves smartish, and I have found that with the Chinese stuff at least, after flowering, come wintertime they will put on more growth and give decent leafy veg again. I have been eating steamed leaves and flowers off a second year cabbage this year too...mark you, my taste buds are as thick as two short planks, you might notice subtle problems with the taste !