I love the Defender but is it too rough for daily use — like Colombo traffic, school runs, etc.
It depends on the model. Classic Defenders (pre-2016) are more rugged, less comfy – not ideal for daily commutes unless you're okay with some shake and sound. But newer Defenders (2020+) are way more refined – comfortable seats, touchscreens, smooth gearboxes. So yes, the newer ones make great daily drivers, even in city traffic.
In SL conditions, most older Defender models (like 110 or 90 with 2.5L diesel) give around 8–10 km/l, depending on load and driving style. Newer P400 petrol versions go lower, around 6–7 km/l in city driving. Not the most economical, but you get serious torque and off-road power. ;)