I spent a while last night going over my previous FAIRS research and having a quick look at a couple of other sources.
I finally found the transcriptions I had made from the book at the West Sussex Record Office (WSRO PAR 95/7/9). It looks like there are details of eleven headstones (some of which are double), but there seems to be at least 20 different individuals mentioned. Plenty of work to be done there then!
I also started exploring the Parish Register Transcription Society baptism records for West Grinstead, and I think I have found John FAIRS grandparents (my 5x great grandparents), and it looks like they were married in Cowfold, Sussex. There are earlier FAIRS/FAIRES in West Grinstead so the chances of going back further still look quite promising.
So there is still lots of work to do. It feels a bit like I am starting on a jigsaw puzzle at the moment, I have all the pieces out in front of me, I now need to get them all turned the right way round and pick out the edge pieces and corners, only then can I start piecing the whole thing together.
I am however still missing one key element at the moment, that is something that is going to keep me interested, something about this family that is going to make them stand out from the rest of my ancestors in their own unique way. I am sure that this will come in time.