We are trying to sort out a holiday with the in-laws (PIL and BIL & family). We live at opposite ends of the UK from BIL, PIL live about 2 hours drive from us. Due to distances, cost and small children it's difficult for us all to get together - it hasn't happened for more than 2 years.
Both families have school aged children so we have to go during the couple of weeks where our summer holidays overlap (England/Scotland). Originally one plan was to rent a holiday home big enough for us all somewhere in the middle, travel wise, but now it's looking more likely that my lot will do the big journey. I'm fine with this as BIL& co have done it more often (to stay with the GPs) and also they have a holiday caravan and we can rent one too nearby - think it'll be nice for my kids to see where their cousins go and it'll be familiar to them etc.
SO today, the PIL have informed us that they are already going to be staying with some friends of theirs in the same area for the week before our chosen week, and so they don't think they will want to hang around for the whole time but will stay 3 days extra, probably in a hotel.
This has annoyed me, not only because I thought they might actually WANT to spend as much time as possible with the grandchildren all together as it hardly ever happens (and actually, the whole thing was originally their idea), but also because their (already set) dates restrict us to having to book the most expensive arrival date/no of nights combination - if we went for the cheaper arriving on a Monday, staying 4 nights we would only overlap for 1/2 nights 
. We will have to overnight on the way down and up as well.
PIL and their friends are retired. DH and I both work and it looks like we will have to use more holiday days than I thought.
AIBU or would this annoy anyone else?