OP, some food for thought:
99% of Brits always lie about where they live: they say the commute is always shorter than it really is and always say things like "never been happier", "never looked back", etc. I have lived in other countries where people find it perfectly normal to say: "Actually, I don't think this area is for me, maybe I made a mistake moving here, I am reconsidering". Brits would never admit that, not even under torture, so when people tell you how great their area is, take it with a truckload of salt
Working from home: no one has a crystal ball. FWIW, my two cents is that most people will work from home more but not enough to justify living too far from the office and enduring a soul-crashing commute.
In SW London you probably bump into other families when you take the kids to the local park. In Surrey that's rarer. You often have a huge garden but fewer parks and farther away from you.
A 5-year old typically enjoys a huge garden. A teenager may not. In fact, teenagers may resent living in the middle of nowhere. You will not like having to drive them everywhere.
This will upset many people living more rurally, but living in London exposes the kids to more diversity and equips them with certain "life-skills" which I dare think are important. It is also important that kids ca move around more freely, more independently, start to learn how to assess potential dangers, etc.
Most commuter towns in Surrey give you the worst of the city and the worst of the small town: you don't live in a bucolic paradise, you live somewhere where you need a car to get anywhere and will spend loads of time stuck in traffic. Quality of life is also being able to walk to Sainsbury or to get to a shopping centre / high street in 10 minutes by train or bus. Most families need two cars, whereas one would have sufficed in London, because train stations are often a couple of miles away with little to no public transport. Oh, and you often have to pay £1k a yea to park at the station. Keeping a car just to drive 2 miles to the station is insane but there is often no alternative.
If you commute to London, the commute is expensive and soul-destroying. A 35-minute train journey to Waterloo can easily mean more than an hour door to door if your journey doesn't end in waterloo. Plus, if there's a problem on the tube or the SW trainline where you live now, you might be delayed by, what, 10-20 minutes. If there's a problem on the line to Guildford you might easily be delayed by an hour.