Alison,
Yes. I know a bit about the area because my family (Wright) was in Prestonpans for about 200 years. They were also Market Gardeners and land overseers for about 60 acres in the middle of the old village of Preston - close to the battle site. I have also done a lot of transcription for the FreeReg from photo images of the original records. I have had a quick look but have not found any Hepburn/Waite couple, nor a James Hepburn.
Another branch of my family is from the Pickering/Middleton area in North Yorkshire. I have been researching them for quite a few years, but could not have accomplished nearly as much without the help of many perfect strangers.
Good Luck with your research, and i hope you always find it exciting.
Elizabeth (Canada)