The damn thing will fire occasionally for about a second and then go out. This can be infuriating as you can imagine.

As a service engineer I assumed I could fix it. I've trawled through the thing and identified a problem but I'm afraid it didn't fix it. She has called a couple of so-called engineers in, who have all told her to replace the whole lot as its impossible to fix.

Now here's the rub. A new boiler is £1,000 and the fitting fee is another £1,000, so surely a couple of hours diagnosis and a new PCB must be cheaper? That is, until you look into the maths.

It turns out a new boiler is £1,000 even on the internet but her friendly supplier told her that if she had a trade account a discount of 50% was available. She's not a plumber, so no joy there I'm afraid.

This has always struck me as weird. If you roll up with a credit card or cash and pay on collection you get penalized to the tune of £500 but if you open a trade account, pay after 60 days or when threatened by the bailiffs, you get a 50% discount. Does this make sense? Surely wholesalers would love payment on delivery?

So it turns out a new boiler to the plumber is only £500 and he gets £1,500 for the pleasure of fitting it. That's £150 an hour and I thought it was only doctors and lawyers who charged that much.

The best bit of it was she is clearly not a gas safe installer, but the supplier didn't care about that and would sell the boiler to her anyway. Hey why not when you are making £500 profit?

I'm thinking of becoming a boiler wholesaler on ebay. I will sell you any boiler you like at 30% off the internet price and keep the 20% for my trouble.

Hasn't anyone else thought of this?