A quote is not an estimate. Once agreed it's a legally binding contract obliging him to do the work for the fee he specified, with the exception of reasonably unforeseen issues, which don't apply here. If he quoted without assessing the job properly that's his problem.
I know little about windows, or much else for that matter, but it's clear that something is pressing down onto this bay window and there's only one thing it could be - the storey above it. Image 4287 shows this most clearly. I'm surprised the glass hasn't shattered. When the bay window was...
"BTW, his quote for the job was £1,350, which included adding a lead apron to the front one side of the other chimney. The price also includes the scaffolding."
Unless the scaffolding cost £1340, you've been ripped off.
You certainly need to make a request of the roofer. Basically to never venture within a mile of your property ever again. What a horrible sight. You need to get an actual roofer to rip all that up and do the job properly.
When I had the roof done I paid after completion, which included about £3k materials and scaffolding. But when I had the kitchens and bathroom done I paid upfront for all goods, about a month prior to delivery. Fitting was after completion. The boiler and central heating system was 10% deposit...
I had mine done last month. Shellcast, but equally difficult. You can't just use a brush. Also, whilst it might help you sell the house, it's not going to last more than a few years. May not even last one.
You can rent a spray gun. I'd recommend that. A fifty quid gun won't work. But you don't...
Likely a bird is building its nest in your chimney, and the sound you hear is dislodged mortar from its nest-based activities. I had this in my previous house, for a few weeks every year, normally between 7am and 9am.
Lucky it didn't rain before he got the tiles on. When mine was done a few months back we got 36mm of rain in 5 hours with 40mph winds - there wasn't a tile on the roof, just membrane.