I went through Gatwick lat Sat- big hassle allow extra time.
Hairdryer & straightner definately in luggage, no where else they will either makeyou transfer to suitcase or confiscate --- your choice.
Medication in hand luggage [ case could get lost] in clear plastic bag and your repeat prescription with it as proof it is yours or letter from the GP, they did not actually ask for the proof but the airline did warn us a few days beforehand so be prepared[ scouts motto].
Liquide etc ie shampoos best put in suitcase, wrap sellotape around opening to avoid leakage & wrap in a plastic bag.You are only allowed liquids in 100ml bottles not one mil over, so easier to pack in case.
Enjoy your holiday , after getting through airport security you will deserve one.