Some of the information you have been given is sadly incorrect. Toiletries for example will simply be confiscated and destroyed because they may contain drugs or other non allowed items. This applies to prescription drugs too. Take the repeat prescription slip with you.
Taking extra clothes in is pointless. Even if you are allowed to have them with you, you will have no means to wash them, well initially anyway.
Concentrate on important items such as spare glasses or reading glasses if you use them. A cheap watch with a new battery is a good idea. So are some comfy shoes. Leave the the credit cards at home and take cash with you; £100 if you can afford it. You will need money to use the phone and buy a few luxuries.
Does this help?
Well, who said life was going to be easy?