I dont know how myheritage does its matches, but that looks like a suggestion rather than a documented paper trail. Did you contact a submitter for further information?
if it were documented, then it would show when he went to Aus, when&where he wed and when&where he died. There isnt an Ascot in Yorkshire for Florence Joan to have been born there, so even that statement is doubtful.
What we have asked for time after time is
Dates of birth for any/all of those Walker-Byefield births
Places (street addresses) for those Walker-Byfield births.
Dates, places, street addresses, parental information, witness names on marriages of those Walker-Byfield kids.
If you really think that the illegitimate 1886 birth is your man, then BUY the birth certificate and we can see whether we can find him/his mother in census to rule him in/out.