Similiar situation here.
Okay, so we do an 8 weekly clean on a £35.00 house in a village near to me. Its quite a nice job, usually enjoy doing it. Ive only spoken to the husband, that was when I priced it up. Since then he's never been in and she has always been distant, so to speak. Indifferent. You get
this feeling perhaps when she's around, if you knock to give them the ticket after the job is done and just to say the gates been closed etc. She reminds me of an ex's sister, there was always an atmosphere when she walked in the room

Anyway, we turned up today and for once the old man was home. He was in the back garden playing with the sprog. We greeted each other in the usual polite way you do, small talk, weather, are you busy and the usual clap-trap. So then he asks if we go on the extension roof to clean the windows above it, to which I reply yes. He mentions that there are a couple of cracked tiles. But that's all he says. So I replied with 'Okay, well we'll get the 47' pole out and do the lot from the ground, we should still be able to do the velux windows, just it'll be a bit of a stretch as the roof angle is so shallow'.
I then ask if there is an issue with water ingress into the property considering the cracked tiles. He replies with 'Well, yes, but its not critical, I wouldnt worry'. He saunters off and Im thinking - Hmmm, odd, but he isnt too bothered, so ho hum, carry on.
20 seconds later out comes the wife. She was obviously rather more irate going by her body language. Anyway we had a repeat of the conversation I'd had with her husband to which I replied 'Ive already spoken to your husband about this and he wasnt overly concerned about it'. She replied with 'Oh, hes always like that!!' Huffing and puffing to herself about her inadequate husband no doubt.
So she wanted to show me in the kitchen where the water had leaked in. Inside, in the kitchen, there was a water line down the ceiling, running directly from the velux window. My response was that she may have cracked tiles above the velux but that line of water looks remarkably to me like its coming from a fault with the velux, the flashing around it perhaps or the unit.
Then, I was invited upstairs to look out of the bedroom window at the broken tiles. Now there were three that were broken. One had about 1/2" of the whole tile width broken off from the bottom of the tile. No disaster, no leak being caused there. Another had a smaller amount broken off, about 1/2" but just 3" wide. No disaster there either. Another had a corner of the tile broken off, possibly 2" - 3" from the corner of tile. So, possibly something going on there, but the roofs felt lining should keep any small amount of water away from leaking into the actual kitchen.
So, anyway, maybe it was us who had done it, I dont know. But why when the they first noticed any leak hadn't they contacted us then? I felt as they couldn't prove it was us that I wasn't prepared to take full responsibility for it. She tried to say it could only have been us as we were the only ones who had been up there. But thats not proof, that's just assumption. Trying to explain to her that there are other ways that a roof tile can reak fell on deaf ears, shrugging her shoulders. She tried to tell me that in the past they've had some roof tiles replaced on the roof at a cost of £150.00. To which I scoffed to be honest. I suggested though that they get a quote, on letter-headed paper that I can have access to and we'll take it from there.
Anyway, she didnt like me implying that it wasnt entirely our responsibility, so she left the room. Although I was polite I also wasn't going to be bullied into paying for something I wasn't sure was our fault. Anyway, her husband was left in the room with me, he was much more amenable. No demands, just someone who was willing to discuss the situation. So, I suggested again he get a quote and I'd be prepared to go 50-50. He was happy enough with that I figured, although the look on his face said 'She (who must be obeyed) isnt going to be though'. He asked us to finish the windows and we'd pursue things once they'd got a quote.
I went downstairs and out through the kitchen again, where she was. I started trying to explaine to her what me and her husband had agreed, but she wouldnt look at me, so i just stood there in silence waiting for her to turn around, it was really comical, she had well and truly thrown her rattle out the pram. Anyway, she absolutely refused my offer of 50-50 and told us to leave. I told her we going to finish cleaning the windows as her husband had asked us to do that at least.
When we'd finished I knocked on the door again to just re-affirm to him my offer of 50-50 should the quote be acceptable. So, halfway through talking to him she comes out the kitchen finger pointing, saying she's spoken to her father, as he's a builder, and he thinks its madness that we were walking on her roof, and that she's going to make sure we lose any goodwill we have in the village and she'll make sure everyone knows!!
She turns her back and storms off. I looked at her hubby, he grimaced with embarrassment, I think, I handed him the ticket for the days work and said 'I think its best we dont come back'. To which he nodded in agreement. Shame, he was at least a nice fella, but he sure has got fiesty one there.

I think 50% is a fair offer all things considered.