I live in Sutton and can shed more light on the burbs.
It has big town centre with a lot of useful shops, a nice cinema with sofas, gyms, dance studios and a bunch of restaurants by the station. The south side backs onto the coutryside and is the posher side but 475k is a more realistic budget around the town centre or north of the high street (less glam but decent).
1 mile west is Cheam Village (Waitrose, independent shops, lovely park, leisure centre etc) and you might be able to get sth in North Cheam that’s within a longer walking distance of the village.
1.5 miles east of Sutton is Carshalton Village (lovely period architecture, ponds, a leisure centre with an great gym and pool, community theatre, well-liked pubs and quite arty). There’s a modern house in your budget that has just come on but you should also be able to get a 3-bed older fixer upper.
All of the above have trains into Victoria (+ London Bridge, + the Thameslink from Sutton). They’re also a fairly short bus ride to Morden tube in case you’re out very late.
The general area is brilliant if you’re sporty with lots of clubs, coutryside on the doorstep for bike rides or walks as well as a public golf course, climbing wall etc.
I’d also say it’s all very family orientated with brilliant schools and quite a few OAPs.