Thanks for your replies. In both cases - should DC be academically inclined (i.e. good enough to get into grammar) - secondary options are good.
Option A (outstanding primary schools) is in the catchment of an outstanding comprehensive with good results (the main building makes it look like a private school). Also, this village is one of the places all private school buses in the (very large) area stop at. I am guessing what's at play is: well-off/committed parents = good state primary school, and some of the kids later go private, while the rest go to outstanding comp or neighboring grammars. It's a very MC place, and we would only be able to afford a 3-bed home in this area at most.
Option B (not-so-great primary schools) is in the catchment of the same grammar schools as above, but the local comp is once again, not so great. This probably reflects the fact that this is a more diverse area than the above - it's a growing town rather than a picturesque village - which is undergoing massive regeneration over the next few years. New developments are opening up (which is what we are looking at there - hence, nice houses, but not so great schools at this moment in time), Waitrose moving in, etc. They are meant to be building new schools, but not in time for DC. Here, we could afford a much bigger home where we would be happy to stay for quite a while.
With Option A, what I like is that DC could potentially go to state school for most of her "schooling life", simply because primary school, comp and grammar options are all fantastic. With Option B, if DC got into one of the grammars (one of the Top 100 in the country), I'd be delighted, but I have been told that many of those who do get in went to prep school rather than the only state primaries we would be allowed to consider.
We have previously thought of sending DC private for secondary school anyway (or even 7+) as there are many very good options around that are commutable from both areas, and therefore never thought about secondary options much. If it weren't for the jobs DH and I have, I would go for Option A straightaway. But I do have the feeling that due to the nature of the work DH and I do, we may inevitably have to go private even earlier than that (too early to tell right now), to make use of flexi-boarding options which you won't find at a normal state primary school. In that case, spending a huge lump of money on Option A seems like money down the drain, if we don't make use of what that extra expense would offer us in return.
DH and I have been discussing this for quite a while, and there is no end in sight. We are going to look at both places again this month to see which area we really would want to move to. At the moment, we wake up having a different opinion each day...