More of a WWYD. Boiler has packed up, no heating for 2 days and engineers like hens teeth. Found one today willing to come around and "have a look" at the end of his day. Very nice guy, tried a few things, but ultimately couldn't fix it. He was here for about 35 mins. As he was leaving I asked him what do I owe for call out and he looked embarrassed and said " I don't know, I didn't fix the problem so you decide". Now I feel awkward, I have no idea what to pay or what the etiquette is. Any suggestions of a fair amount would be gratefully received. I'm not on the breadline but like everyone having to be careful and a no doubt big bill coming up. I'm also panicking a bit as it's obviously freezing and I have 3 young kids with no heating, thankfully we do have hot water with immersion .