Thanks all. I need to go through the figures in more detail but do think that we can cut back a lot. We typically go away several times a year, kids do loads of activities etc. One key point though is that I am spending £1,200 per month on after school childcare and around £300 to £400 per month on tutors, both of which we wouldn't need when DC2 goes to secondary (am def not paying for tutors and private school). Issue will be for the 2 years that DCS is still at primary as we will still need childcare then.
Regarding letting DS1 start at the local secondary, how do I know he is not doing well? I am not expecting any massive dramas but think he is at risk of coasting/underachieving. Not sure this would become apparent until we get his GCSE results! I think DS would be ok/happy there.
As for moving into catchment of a good state secondary, we almost did this last summer but, having work out the cost of moving (stamp duty, estate agents fees etc) as well as the massive upheaval and that we would be getting a smaller place in a worse area, decided against it at the time but thought we would revisit for DC2 who will go into year 5 in September. I thought we would afford the fees for private but, going through it now that we are getting closer, I am worried that paying for 2 is going to be very tight and will mean cutting back massively on holidays and other luxuries.
I think, at this point, we will wait to see what, if any, offers he gets from privates and then decide. I am tempted to send DS2 to a private school for 2 years then move so that DC2 gets into a good secondary then try to get DS1 in via the sibling policy ) but accept that posters think this is a bad idea! Maybe local secondary for 2 years then move, or move even sooner and go on waiting list. If we move though, we will still be spending at least 70k on stamp duty so we still pay, just in a different way.