you don't usually cover camellias, frost on buds is only really a problem if they get the early morning sun.
so personally I'd remove them. they thrive in the uk with out protection..

We live in the north of Scotland and don't put anything over our Camelia. If you are going to try to protect yours I am not sure why you would remove the protection in mid-January as, generally, some of the hardest frosts can come in February/March. Indeed, our most damaging frost his year was in May!!!!!

Get 'em off - unless you've got some variety that should be grown in a hothouse (and I don't know of any), they're more likely to come to harm from being covered than anything the weather does.

The point about early morning sun hitting frosted buds is valid - hopefully, they're not planted where that can happen.

Hi, welcome to GoY, as said above, most Camellia species are completely hardy, and need no protection, other than keeping them out of early morning sun.
However there are some species that do need some protection, such as; C lutchuensis, C Harold L Paige, C Granthamiana, C Jean Pursel, C Grijsii, C Fraterna, these are all half hardy,which means they can withstand temperatures down to 32f, but C Nitidissima is frost tender, which means it can only stand temperatures down to 41f, and in the UK, should be grown in a cool greenhouse, but I think you're more likely to have the common Camellia, which is C Japonica, and this is completely hardy, so I agree with the others in saying to take off the bags, Derek.

Hi Steve, it certainly is, but I usually work in old money, :-) Derek.