Hi there Kris,
Fantastic! Well done for finding them in the 1841 and 2 daughters I did not know about!
As to your other query, that is very interesting about the alternative use of surname. However I am sorry I cannot help you here, the Burt connection via the daughter Susannah is one of my branches which I have found out very little about, other than the parents, Robert married to Mary Ann Manning which is on the IGI.
My connection is then via Susannah's husband, Walter Gibbons and so on and so on, so I am thrilled to find out about the Burt parents also and 2 more children. I do know via FamilyHistory Online that Susannah died in 1844 and was buried in Woolpit, presumably then the family moved onto Ipswich. Certainly Susannah and Walter lived there all their married life, until Susannah herself died relatively young in 1873.
I also have yet to pursue the Manning family line; however research is unending isnt it!
Very many thanks again
Alison