1. Check Gas Safe Registration (Non-Negotiable)
If any work involves gas - boiler installation, repair, servicing, or gas pipes - your engineer must be Gas Safe registered by law. This is not optional.
How to check:
Ask for their Gas Safe ID card, or verify on the official Gas Safe Register at gassaferegister.co.uk.
Warning signs:
Any engineer who says Gas Safe registration “isn't necessary” or can't show you their card. Walk away.
2. Look for Manufacturer Accreditations
For boiler work specifically, look for manufacturer-accredited installers. Worcester Bosch Accredited Installers and Vaillant Advanced Installers have completed specialist training and can offer extended warranties - up to 12 years vs the standard 2 years.
3. Check Reviews - But Be Specific
Don't just look at star ratings. Read recent reviews (last 3-6 months) and look for:
- ✓Mentions of punctuality and communication
- ✓Whether they cleaned up after themselves
- ✓How they handled problems or complications
- ✓Specific mention of the type of work you need
Check:
Google Reviews, Facebook, Checkatrade, and Trustpilot.
4. Get a Fixed-Price Quote
Always get a written, fixed-price quote before work starts. Avoid any tradesperson who will only quote by the hour without a clear scope of work.
What to ask:
“Is this a fixed price or an estimate?” and “Are there any circumstances where the price could change?”
5. Check They're Insured
Any reputable plumber or heating engineer should carry public liability insurance.
What to ask:
“Do you carry public liability insurance?” A professional will have no problem confirming this.
6. Ask About Guarantees
Good tradespeople stand behind their work. Look for:
- ✓Workmanship guarantee (minimum 12 months on labour)
- ✓Manufacturer warranty on parts and boilers
- ✓Clear process for what happens if something goes wrong after the job
7. Local Knowledge Matters
A local plumber who knows the Milton Keynes area will understand local water hardness (MK has hard water, which affects boiler maintenance), typical property types, and can respond quickly in an emergency.
Red Flags to Watch Out For
Asks for large cash payment upfront
Can't show Gas Safe registration
No fixed-price quote
Pressure to make a quick decision
No reviews or very few reviews
No physical address or company details
Why Homeowners Choose Plumbline MK
- Gas Safe registered engineers (verify us at gassaferegister.co.uk)
- Worcester Bosch & Vaillant accredited installers
- Fixed-price quotes - no hidden fees
- 12-month workmanship guarantee
- 100+ 5-star reviews on Google and Facebook
- Local to Milton Keynes - fast response times
- 24/7 emergency cover
Not sure if you need a service or repair? Read our guide on the difference between a boiler service and repair.