Bit late back to this but good schools in MK include:
Infant - Ashbrook (Two Mile Ash), Holmwood (Great Holm), Glastonbury Thorn (Shenley Church End)
Junior - Two Mile Ash (in Two Mile Ash
)
Primary - Caroline Hasslett
Senior - Denbigh (Shenley Church End), Shenley Brook End, Oakgrove. Plus you can also try to get into the grammar schools in Buckingham (Royal Latin), Aylesbury (Aylesbury Grammar for boys and Aylesbury High for girls) or Leighton Buzzard (sorry, not sure of the names) - but I'd look at transport to them - there are organised coaches but if all else is equal then it would be good to be closer to the pick up points for your chosen school if that makes sense...
There's a school finder on some property websites and I think on here - but you have to play around with the settings because instead of taking a list of all the schools in MK, then giving the top 10/20 etc, it takes MK to be a point (based on a postcode) then if you ask for the top 10 schools it looks for the 10 closest schools and ranks them, meaning that the schools that comes top of the 'top 10 schools in MK' list is actually only about the 7th best school in MK - the better ones only show up in the Top 20 or Top 40 schools in MK lists
because they're further away from the centre. and what's worrying is that they really didn't get why this was a problem when I emailed them to ask about the differences - I suspect it was designed by someone who has no idea about choosing schools in medium sized towns. But it's worth bearing in mind!
(And conversely when you search for secondary schools because there are many fewer schools, if you do a search on the top 40 secondary schools in MK, the best one comes up as something like in Northampton (there's a very good boys school there!) because it just looks for the closest 40 secondary schools to the point defined as the centre of MK, regardless of the fact of how many schools there are in MK!).