Not long, about 20-30 minutes but they'll keep you in for a few hours.
The tea and toast afterwards are nectar. You should be home by about 6 and possible feel quite drowsy. Do NOT cook any food by yourself, get a son to spoil you x
Sqad is correct of course. The Endoscopy i referred to was the Gastroscopy, given under local anaesthetic spray, took about ten minutes, bit uncomfortable.
its not anaesthetic as such -you are not unconscious. you have what they call sedation or "waking anaesthetic" which leaves you compliant and still able to follow instructions but has the added benefit that it gives you a retrograde amnesia, meaning you don't remember