The number you should know first
Your top 4 maintenance contractors do 62% of all jobs. One of them, A&G Plumbing, charges 34% more than the next cheapest gas-safe firm on identical job types. Switching them saves an estimated £4,800/year with no impact on speed.
Based on 78 callouts over the last 12 months. Median cost-per-job for A&G £218 vs Marsden £162 and Crane Heating £174 on like-for-like categories (boiler/heating).