Due to the arrival of a baby last year my B&W 601 S3's on stands need to
go....

Obviously I am thinking along the lines of the Bose acoustimas 5 however i
have read mixed reviews. The speakers will be connected to a NAD 302BEE.

I'm looking more for small form factor rather than size and my budget will
run to approx £400

Any ideas on options and thoughts on the Bose units?

Why would the Bose be any more child-proof than the B&Ws? And they
aren't THAT big. Are you sure the Boss isn't just playing power
games: "There's no room for YOUR toys any more..."? :-)

I've heard the Bose. Overpriced and mediocre fashion objects. If you
aren't to be allowed good speakers, get something really small and
cheap. You can have your 601s back after the divorce :-)