Hi,
Tried looking again using the details you gave, but like you have drawn a blank. Sorry. I think he may not have been born in Oxford, or if he was , his surname may not have been Rakes. The possibilites are many. I have a 3 x great grandfather who appears to be illegitimate from the only baptism record we can find, but he puts a fathers name of John on his marriage certificate. I have another family in Wales who were all born illegitimate registered with their mothers surname, but when she eventually married they were recorded on censuses under the step fathers surname - some married under his name, others their original registered surname. Perhaps if you get his second marriage certificate or his death certificate they may have some additional info on.
Good luck