Do not fill 4/4 full of water and 1/2 lt of washing up liquid.
DO NOT fail to notice Mrs TYA looking at you with "That look"
The problem is with the 4/4, Mrs TYA has quite rightly understood that when you have put 4 forths of the volume in something it is full, years of cake making probably re-inforced this with her, and maybe having to clean the oven as well! Her appreciation of the fact that once you have four forths of something in something you can't get any more in, (I know I didn't have to put the bit about four forths again, but felt it was best to keep on Mrs TYAs' side ) has caused her to give you "That Look"