First time poster here.
I'm currently nearly 28 years old, married with two kids living in the West of England. My wife and I own (rent from a bank really) a three bed house currently worth around £200k with a £114k mortgage. Our house is fairly small (British houses are so much smaller than American, you wouldn't believe) and are considering having a third child.
A stone's throw from our current house is a new housing development being created which has some 4 bedroom houses planned, although they are not currently for sale and won't be built for another couple of years. We have contacted the regional manager of the development company, as a neighbour of ours managed to discover his email, and said we were interested in buying one of the 4 beds off-plan. We'd expect the houses to go for £330-350k given the shortage of 4 beds in the area. We are planning on making an offer for £275k for the house, with a ceiling of £300k. We would also be eligible to a government Help To Buy loan, which would cover 20% of the house value interest free for 5 years and then be pegged to inflation. In the intervening 2 years, we are planning on paying off our mortgage aggressively, so we should have at least £100k in principal by the time we switch. This would put our mortgage at £140k, but we would be eligible for the lowest possible rates due to the LTV.
We also have a small debt (£4.5k) to my mother that we will have paid off by next year as she lent us money to clear the second mortgage on our current house [Interesting story - Our current place was a new build as well, the home builders gave us a 15% stake interest free for 10 years worth £27k. but we negotiated to pay it off after 2 years and as an incentive they knocked it down to £20k if we could pay it off within the calendar year, so we begged, borrowed and sold one of our two cars to do it.] No other debts, apart from student loans. Both my wife and I make the minimum contributions to our retirement pot to cover all the matching of funds our employers offer. Minimal savings currently as we are just at the tail end of my wife's year of maternity leave.
We are currently fairly positively disposed to this idea of buying the new house, but I'm also wary of being hit by reversal in the property market between purchase and actually moving in. Advice and opinions appreciated and further details could be supplied if needed (maybe I've over-shared already!)