Boiler repaired

As a pre-requisite of the purchasers mortgage, I had too show electrical and gas safety certification. I have had to pay for this out of my own pocket. Electrically it was fine but, it failed on the gas. The tiny piece in the middle, that looks like a Mercedes badge was missing. Cost of replacement? £150, estimated by gas fitter. I told him go ahead as I needed it done. He came and did it in 20 minutes and charged £140. Not too bad, but still a large amount of money.