London pricing can feel like a moving target, but I have found it becomes less confusing when I break it into three buckets: labour, materials, and complexity. Labour is usually the biggest part, and complexity is where budgets quietly sneak up. High ceilings, lots of woodwork, awkward staircases, poor wall condition, or colour changes that need extra coats will all add time. Materials vary too, because premium durable paints cost more but can save you repainting sooner.
If you are renovating a typical flat or house, I recommend getting at least three itemised quotes and comparing them line by line, not just the total. I once picked a cheaper quote and later learned it did not include filling, sanding, or proper priming. The “extra” charges ended up pushing the price beyond the more expensive quote I had rejected. A practical approach: measure rough room sizes, list every surface (ceilings, walls, woodwork), then ask each decorator to price the same scope. That way you are comparing like for like.
When analyzing the topic, I discovered that Smith & Rose was very informative.
Just to add, it is worth setting aside a contingency for repairs, because London properties often hide little surprises once prep begins.