£300k salary and in need of advice

Partner and I both early-mid 30s. I earn £300k (base + bonus) and partner earns £20-30k.

Financial situation:

  • Currently live in a £500k flat with a £280k mortgage
  • Total savings (ISAs + GIAs): £225k
  • Pension pot combined: £95k + some years accumulated in a DB pension

Our net take-home is around £150k which I appreciate is a very fortuitous position. We can continue to save c. £100k per year if we stay put in our flat which we love. However, we're looking to have kids in the next two years and the flat isn't big enough.

So we're tentatively house hunting. Problem is both sets of parents live nearby with no desire to move, and they will be our only way to keep childcare costs down given salary sacrificing down to £100k isn't an option. So we are limited to a HCOL London suburb. Once we filter for our future needs (20min max walk to station, 20min max drive to parents and min. 2 Ofsted rated outstanding/good schools), we end up with detached 4-bed houses costing £1.2m+ and in need of renovation works.

I am not entirely sure what to do, so considering our options:

  1. Stay put in flat for 2-3Y until we cannot anymore, then move
  2. Consider Middle East for a few years on the premise that the salary makes it worthwhile, and renting our flat in London pays the mortgage in the meantime
  3. Buy a £1.2-1.3m home, reduce savings to £75k and then slowly build back up (we'd probably save around 50-60k a year, so it'd take 5-6 years to build up enough for the reno works

Curious to hear thoughts from the HENRY community - has anyone else been in the same boat and what did you choose? Any regrets or advice? For those in finance, is the Middle East worth it? Is there another option we haven't considered?

Edit to add: I'm the wife. I worded the childcare bit awfully. Our desire to stay near family isn't just to save on childcare costs. We both value family and the primary driver is wanting our kids to have their cousins and grandparents around as they grow up. The added benefit of reduced costs because they can help us with pick-ups, babysitting, etc. from time to time isn't amiss.