Great to hear from you - and in Australia - I have not got to any Australian links yet but I am a decendant of William Seabrook and Martha Dyer, as far as I have found so far.
I have recently moved house, so my records are not that accessible, but I do have a copy of either Olyffe Seabrooks birth or marriage certificate - its very confusing as it appears to say Olive!This is a female name of course, but I do not think they were too good at spelling then.Anyway the rest of the certificate gives no doubt Olive is male, so that's OK. I will try and find the box with the details in.
I do have the William Seabrook/Martha Dyer decendants logged I think. Jan Seabrook, Surrey, England