OK, let's try another approach. You say that Kathleen's father was Daniel, and she had siblings William who died in WWI, Florence and Jane.
The CWGC at
http://www.cwgc.org/cwgcinternet/search.aspx has two matching entries:
(1) William BLOWERS, Royal Naval Reserve, died 15Feb1918 age 56. Son of Charles and Sarah, and husband of Mary Ann. This isn't the right one - wrong parents names and too old.
(2) William Frederick BLOWERS, 6th Dragoon Guards, died 26 May 1915 age 23. Son of Mr & Mrs Blowers of 44 Waveney, Ipswich. What a shame they didn't list his parents' first names. His age is OK, so born c.1892, and we should find him age about 9 in the 1901 census.
A search of the 1901 Census reveals 4 possibles,
(a) Willm. age 8, at 90 Waveney Road, Ipswich with parents Josiah 33, and Florence 32, and siblings Violet 12, Percy 5, James 3, and Bessy 1.
(b) Fredk.Wm. age 9, at 7 Mariners Street, Lowestoft, with parents Henry J. 31, and Alice E. 31, and siblings Frank S. 6, Florence 5, Henry 2, and Edward 1.
(c) William, 10, at Covehithe with parents William 38, and Harriet 36, and siblings Henery 9, Harriett 7, Emma 8, Benjamin 1, and Edward 5.
(d) William J. age 11, at Rookyard Farm, Theberton, with parents William J. 34, and Elizabeth 33, brother George, 1, and Elizabeth's mother.
The first of these seems to be a good match for William, as his parents are still living in the same street some 14 years later. No sign of Florence or Jane in the same family, although Florence is William's mother's name.
Also none of those have a father named Daniel, so let's look for him. There seem to be 2 in Suffolk;
(i) Daniel, 36, at East Green, Kelsale with wife Polly 36, and children Christy C. 4, Jane A. 2, and Herbert W. 5 months.
(ii) Daniel, 30, at Red House Farm, Mells with wife Eliza 35, and son George E. 1 month.
The conclusion from these searches is that there does not appear to be anything that links Kathleen's supposed siblings (William, Florence and Jane) with her supposed father Daniel - and in fact the parents of the William who died in WWI were Josiah and Florence. Sorry that I can't be more positive, but that's where the information you provided has led the searches.