I work in Endoscopy but can only answer for my trust and each will be different. But here's my two cents!
What happens when I first arrive for the appointment? Do I go into a ward/bed or just wait in a waiting room?
If you've not been talked through a consent form and signed for the procedure then they'll take you in and go through the procedure and get you to sign if you're happy. Then you'll be taken to a waiting area to change before going into the room. Smaller departments you'll likely walk into the room. Some take people on their trolly.
• What do I wear during the procedure? Can I wear my normal top or will I wear a hospital gown? Can I wear a bra?
We ask for bottom half off but allow tops on with gowns over the top. We also have dignity shorts that have a little flap at the back for access. You'll be well covered during the procedure and we are all just looking at the screen!
• I wear fake tan and nail polish - is this ok or does it all need to be removed? I know for operations things like this are quite strict but not sure if it's the same for a colonoscopy?
The fake tan is absolutely fine. If you're having sedation it's ideal to not have nail varnish as they will need to monitor your oxygen levels and the nail varnish can make that a bit trickier. I wouldn't worry too much though, even if you can just have one nail with it removed it'll help!
• I want to have the sedation, will I need someone in the hospital with me or can they wait in the car and I walk out to them afterwards?
You'll need someone to pick you up from the department and stay with you after. But they do not need to be in the department while you have the procedure. We call lifts when the patient comes into recovery so that they can come back to collect.
• Can I wear makeup?
Absolutely, if you'd prefer that's absolutely fine!
Other tips... take a dressing gown, slippers.. and a book! Depending where you are on the list, you coulr be waiting a bit. You may well be offered gas and air to help with some of the uncomfortable corners, though some with sedation just don't need it and some decide to have it. They'll be keeping a close eye and if anything becomes uncomfortable, they'll be able to change position/offer gas and air if you're able or potentially more sedation/pain relief if necessary.
Once the procedure is finished they'll take you to the "ward/recovery", check your obs and call your ride home.. offer tea and biscuits hopefully!
Good luck, it's absolutely normal to feel anxious but soon enough it'll be over and done with.