How much would you borrow?

Doozergirl

I'd consider fixing your rate for five years so that you don't have any surprises in that time with interest rates. Elongating the term and then overpaying when you do go back to work will bring your eventual term back down to where it should be or you can remortgage for 20 years after 5 years on the longer term

You will have tax credits, child benefit to add to your partner'sincome. |If you buy a short-term house now you will cost yourselves money if and when you move to a larger house that suits you better in the long term.

You are evidently careful with money so I see no reason not to borrow more to get the right house. If you can do £70k within your means then I would buy the right house for your needs now. £10k in contingency will pay the mortgage for a good while if things go wrong and you can drop down to interest only if the worst came to the worst for a while.