Thank you for the replies. Iam very grateful for any help and ideas!

Jenny - Thanks, yes we believe that is Percy as a child, as my husbands grandmother remembers Lena (Bennell) telling her how he used to live with them when they were little, and there is no trace of a Percy Bennell being born or dying so we believe they just gave him their name on the census. In the 1901 census, he is living with his father Thomas Stratford and his wife and children (who grew up to believe Percy was their brother) I still cannot find him in the 1911 census, and am still stuck with his birth
I have followed Percy Clement Stratford and found his birth entry, and on later census' I also believe he married a Rebecca and isn't our Percy unfortunately.
Robert - Thanks, this is the entry which leads us to think perhaps his mother's name was Hawes, however we cannot find any other connection with Hawes or who is mother may be and so are not sure if this is the right certificate, although I can't seem to find a Thomas Percy Hawes on the census either. Such a puzzle! I will keep trying with the Plumridge link. Ive hunted through lots of Wycombe baptisms, where his siblings were baptised and am now looking through workhouse baptisms.
Any other ideas greatly appreciated and thanks once again for your time,
Alice.