Neighbours Dormer question and my roof on Victorian Semi

Hello
My neighbour has almost finished their L Shaped Dormer and the Builders/Roofers have damaged my roof etc and have now after a lot of chasing they are working to make repairs (they were standing on my roof to complete the Dormer - i consented to this under the understanding that they repair afterwards as i dont see how else they could have completed the job - i get on with neighbours...etc.)
They do seem a bit Cowboyish as i had leaks and damage that could have been avoided, not to mention debris falling on my property dangerously, Anyway this is in the past but i am worried that they will bodge the repairs and i wanted to know how the shared Parapet wall should look after the roof repairs. they did cut into their side of the Party wall and insert steel etc, they have now tiled the side of the Dormer facing my property and have put some lead flashing ( i think its called) on top of the Parapet which looks to be sloping towards my roof so i will collect all of the water, whereas before the water would fall either side of the small domed shaped long tiles that sit on top of the Parapet wall. Is this normal and should that material be used and if it is what should it look like (if you have an image that would be great) any other advice would be appreciated, i .e things to check once repairs are done.
If i am not satisfied (i will be reasonable) do i bring in my own roofing company to repair?
Thanks in advance

Pics of the work would be useful ......

Thanks here are a couple of pics

I wish the rules would mandate the raising of the parapet wall. Then we could put an end to this nonsense.

Does this look right to or will i be collecting a lot more rainwater than i was previously?

If the wind is blowing in to the dormer side you will probably collect a little more water, if it's blowing the other way probably a bit less. Whether it causes a problem or not will be a matter of fact. If you do get a problem, then you can make a claim, but it looks reasonable to me and there is little to object to just because you don't like it.

Thanks i didn't think of it like that but its a fair point! It's not so much that i don't like it i just lost trust that the job would be done properly. as long as i don't get any leaks and the remedial work does not impact on the property value following a survey etc then all is well. Thanks again for commenting