Thanks all this is super useful. Have to say I had not even considered being able to get off-road parking/garage or a detached house - those are just not on our radar in this part of North London (zone 2). It would be amazing to have off-road parking but we never have had it so I guess won't miss it too much, though checking out the parking situation at different times of the day is v. sensible. We don't use the car that much - i.e. not for commuting and don't anticipate using it for a school run - and we just have one.
I think almost everything we look at will be terraced, but good point about the advantages of semi-detached, even with only a narrow alleyway. Hadn't really thought of that.
We have chosen the area partly with schools in mind (we are in a non-church state-primary black hole where we are at the moment), though will obviously need to keep an eye on precise catchments etc. It's an area with several decent primary schools, though, not just one, which we like.
Big hall for the buggy and general detritus is high on my list - at the moment we have a tiny shared hall, with a front door at the top of a steep flight of steps, and then more stairs inside to our door. Doable with one toddler but I definitely want something more convenient for the double-buggy stage we are about to enter . . .
At the moment we are v. lucky and both have a study. Would be amazing if we could keep that but realistically may be an area for compromise.
DH doesn't "get" the garden thing at all and is scared of the maintenance but I think it is a must if at all possible with two small children. Good points about checking sunlight situation in the garden and view from kitchen to garden.
Large bathroom would be lovely actually, ours is nice but tiny.