5 year old DD awful behaviour at home

[Bugaboom]

Since about Christmas my 5 year old DD's behaviour has been awful. She's an angel at school and doing well. She has a 7 year old brother who is very easy going.
Everyday there's a battle with getting dress. Any type of sleeve drives her nuts. She kicks off at the least thing. Latest is screaming she hates us. Kicking, hitting. All new behaviour but getting worse.
We've got time out for bad behaviour and one night she had one of her dolls taken away for a night (after a warning) and she got her back the next day when her behaviour improved.
I've just gone through a reward chart with her and she's gone mad again saying no she won't do it.
I know we have to be consistent and this could take a while. But any tips and advice would be really welcome. It's been a bloody awful weekend.

How are her friendships at school OP?

Good. She has lots of friends and it's a nice year group. We've sat down with her to figure out if there's anything wrong at school and there doesn't seem to be.

Try a chart with rewards and consequences too, clear rules, clear consequences and consistency should make everything easier. Look online for "if/then chart", there are different good ones.

If the problem is getting dressed have her go to school in her pyjamas. She and the school won't like it and maybe it will get her to get dressed. Also, as others said, find out if there is a underlying issue.

My 4yo DS has been like this off and on for a few months. Sometimes I feel like we’ve cracked at (he gets dressed fine atm) but I end up shouting at him to bring his teeth as he just won’t do it. We have a reward chart which has worked so far for everything else (except teeth!) is she physically able to get dressed? Maybe she needs help?