Leni - you need to draw up a pros and cons list for each, them sit down with your DH and go through what factors are most important to each of you. No one on here can tell you which is the right option for you, because we aren't you.
If it were me I'd go with the Beckenham place because I always prioritise location over space, ownership over part ownership, the potential to add value over right at the top of the price bracket already, and two storeys over one. Noisy neighbours above your head can be pretty hellish! If I remember correctly didn't you say the other place fronted onto a busy road? That would also put me off, especially given your ds will be at the mad running about age before you plan to move.
However, if you work from home, space and a swanky interior might be more important... Sooooo, no help really 
But back to babies - for those of you going through the hand chewing phase, the answer is a gummee glove. It's fab. DD spent ages crackling the crackly patch and trying to shove the chewy bits in her mouth. She's not really big enough to properly chew it, but she gave it her best shot, and saved the skin on her hands from another evening of being slobbered on.