The cabin will not go beyond row 8 on an LGW A320 and CE is sold out so it's possible you'll get allocated row 8 T-48hrs if you cannot select at T-7 days. Though considering it's half term there is likely another family in the mix too.

As you say likely no food choice by row 8. Kids meals in Dec/Jan was a rather unappetising mac and cheese , not sure how often that changes.

In an ideal world BA would allocate the seats for families in advance when the available seats goes below a certain point, would probably save a lot of hassle but not sure the tech exists to do that currently