✅ Look for – blockages don’t wait for 9 AM. ✅ Ask if they use CCTV surveys – any firm working blind is a red flag. ✅ Check they cover postcodes CB1–CB5 (the full city area). ✅ Verify they are fully insured , especially for commercial work. ✅ Prefer a company offering no-dig patch repairs – it saves your landscaping.