Yes, you can put shampoos etc in THEIR normal containers in your suitcase. You will be able to put your hair straightners in your hand luggage, but as you can see from the following hand luggage restrictions you will have to take them out of your hand luggage to go through the x-ray machine. You are only allowed ONE piece of hand luggage, so what I do is take a bag (no bigger than on the following regulations) and leave room for my hand bag to fit it in when I go through security. If you are only using a hand bag it will have to be a biggish one to fit your hair straightners in it!