Surprised you are on low residue so far out - the advice when I had them was from 2 days out at most, so Saturday & Sunday for a Monday examination. In fact the timings I was given varied according to if you were having a morning or an afternoon exam.
Also:
https://www.nhs.uk/conditions/colonoscopy/getting-ready/
BTW I had one with sedation and the second with gas & air, I'd go for gas & air if I ever have to have another one. I was thinking the sedation was like I had for an ERCP - couldn't remember a thing - but it was much lighter. I found the gas & air very effective, plus I was allowed to drive myself home.