I lived in Kenley until 2018, was there 4 years, that was after many years in Peckham/ED so very similar to you. I really liked it there, it feels quite a friendly place and my ds who was 3-6 enjoyed being there. It’s fairly diverse, unlike some suburbs which I liked.
Purley itself is ok if a little bland, there’s not all that much to the high street but there is the bloody massive Tesco. Never felt unsafe there myself, I would walk from Purley station to Kenley after work often around 9pm.
Ds was at Harris in Kenley, although it seemed ok and gets good ofsted reports it did seem to have very high staff turnover. There’s a large secondary up in Riddlesdown which is fairly well regarded.
In Kenley the more expensive roads are above the station on the hill- the houses in the valley are cheaper, but are walkable from Purley station which has much better links than Kenley which is a slow, stopping service.
What I really loved was the proximity to green spaces. There is Riddlesdown common, Kenley aerodrome and common and Foxley wood is a hidden gem. It’s about a 10 minute drive to get you to the North Downs way in Caterham. Also v good for the M25 which is also about 10 mins drive.
I have lived in quite a few south London areas and despite being Croydon council, I really liked Kenley.