Ubik, if you were interested, good on ya, for it is a fascinating subject and that era of the Anglo-Saxon overrunning of Britain has been immortalized in the King Arthur tales.
However, you could spend from here to eternity on the internet trying to research the issue of how the Christianization of Anglo-Saxon England, which began in 597, may or may not have been influenced by any lingering Romano-Celtic populations...and not be able to learn enough to come to an informed conclusion.
I skimmed through Chapter Nine. Not really the greatest work. It said nothing about the issue above, in any case.
I think a tip-off concerning the suitability of this "e Book" comes from who published it:
SOCIETY FOR PROMOTING CHRISTIAN KNOWLEDGE, NORTHUMBERLAND AVENUE, CHARING CROSS, S.W.; 43, QUEEN VICTORIA STREET, E.C.; 48, PICCADILLY, W.; AND 135, NORTH STREET, BRIGHTON.You really need to develop some googling skills. it isnt hard.
http://books.google.com/books?id=75Ohv8O6dJIC&pg=PA1&lpg=PA1&dq=Christianisation+of+the+Anglo-Saxon+Kingdoms&source=bl&ots=m_LrVtHMkf&sig=XUqzFPbMb0jrwiT8aHD3KoQ__hU&hl=en&sa=X&ei=MVFHU6eUJpKmsASPnoG4Ag&ved=0CFQQ6AEwBw#v=onepage&q=Christianisation%20of%20the%20Anglo-Saxon%20Kingdoms&f=false
http://en.wikipedia.org/wiki/Christianisation_of_Anglo-Saxon_England
http://en.wikipedia.org/wiki/Anglo-Saxon_Christianity
http://en.wikipedia.org/wiki/Anglo-Saxon_England
http://histclo.com/chron/ancient/ger/inv/eng/ask-ch.html
https://www.uni-due.de/SHE/HE_GermanicInvasions.htm
http://books.google.com/books?id=FUufOm0KTcgC&pg=PA1&lpg=PA1&dq=Christianisation+of+the+Anglo-Saxon+Kingdoms&source=bl&ots=XzYYxpZPnU&sig=F6nXWLdA5s3wy_Tj0Vwg2hRrmOM&hl=en&sa=X&ei=MVFHU6eUJpKmsASPnoG4Ag&ved=0CFEQ6AEwBg#v=onepage&q=Christianisation%20of%20the%20Anglo-Saxon%20Kingdoms&f=false
http://books.google.com/books?id=XjTI-RGgrUIC&pg=PA190&lpg=PA190&dq=Christianisation+of+the+Anglo-Saxon+Kingdoms&source=bl&ots=HDXDgDifQS&sig=UCZ-Vu_LyzrQDYbrV9OaXEMTEWA&hl=en&sa=X&ei=IlJHU5KIA7agsQTLxoEY&ved=0CDYQ6AEwAjgK#v=onepage&q=Christianisation%20of%20the%20Anglo-Saxon%20Kingdoms&f=false
http://www.britainexpress.com/History/Early_Christian_Britain.htm
http://www.ukessays.com/essays/history/exploring-the-christian-mission-in-anglo-saxon-britain-history-essay.php
My fingers are getting tired. i suspect I could paste links here for hours.