I have had a read through the discussion there and it gives me some really good info. I guess the problems that I face are that the array contents are not enumerated values as such - the example I have given above is more a representation of what I have trying to solve.
I have added a field to the person which is a interests count, so for bob this would be 3 and for Jim it would be 2.
I also went down a avenue of tweaking the scoring so that the score for each document was effectively how many matches in the array the the document hit in relation to the search query. I was hoping I could then use this in the filter script, but I cant find a way of getting hold of a documents score value in the filter script context? If I can get that I can solve this.
So distilling this down a bit to one simple question - is there a way of getting hold of a documents score value in the filter script context?