LO enjoys bathing at home but when she baths at my mum's home, she will cry hysterically. Any mummies experience this? If yes, what can I do? Will she react like this when we are overseas?

Naked and at unfamiliar surroundings, for me I will freak out too. If you can bathe your LO at your mum on your own then slowly let your mum take over so as to let baby get used to another caregiver. If you are using a tub, get the same tub. My LO refused to sit in the tub until we got something similar then she started playing inside. Put in some toys too to distract your LO.