I also would avoid things like coloxyl unless absolutely necessary. Since stopping solids helps the poos, then it doesn't really seem necessary. Rice cereal is bad for that sort of thing, so maybe just avoid that at any rate.
And also have to agree that settledness/sleeping doesn't say anything about whether a baby is doing well on bf or not. It's quite common at this age, for example, for babies to go through a period of separation anxiety that may see them waking up more often. Same if they're learning to sit/crawl or do anything new.
BLS is a great way to go, particularly if you're uncertain about readiness. Your baby will decide for himself.
I must say since bubby was sick a few weeks back his sleep has been not that crash hot, that said during that time he started sitting up and also saying Mum and Dad and i know that when they start doing all these things their sleep is affected. I have never given my children solids with the hope they would sleep better, as i know there sleeping patterns has nothing to do with their readiness for food. I think i will look more into BLS.