Help wanted with health issues

Thursday 9th February is my barium enema xray so today I was only to eat low fibre food. As the xray dept didn't tell me WHAT to eat I ate two slices of white toast with the minimal of margarine (& black coffee which I'd have anyway) for a late breakfast then three small white rolls with chicken breast & a teeny bit of mayonaise so it wasn't so dry. I'd Googled for low fibre diets & it said I could eat chicken also mayonaise but I really wasn't sure. I do not want to have to repeat the xrays if I've done something wrong!

Tomorrow at 7.30am I have to add a strong laxative (Citramag powder) to 200ml of hot water then cool it & drink at 8am then I have to take a 2nd dose between 2pm & 4pm. I can eat a bolied or poached egg with white bread for breakfast after drinking the 1st Citramag & the same for lunch (with cheese & clear soup if I want) before the 2nd Citramag. nothing solid to eat afterwards till after the test at 10.20am Thursday. I'm allowed black tea, black coffee, Lucozade, clear soup, water, fizzy drinks tomorrow & Thursday.