Yes, Anthony had an older brother John, but I haven't checked his children or marriage. Do you have dates for these?
I have a few Gardner details and some Gardner cousins are still living here, my late mother was a Gardner and her last sibling, Noel, only died earlier this year.
You can visit my tree on Genes Reunited and see if this is yours too, if it is and you have queries, I can look up at the Priaulx Library, Guernsey, but not for a couple of weeks
Best wishes
Graeme