AIBU to saw off my neighbour drainage pipe?

[Lavendersblue11]

About two years ago, my neighbour turned a brick out house backing onto her property into a bathroom. Two walls of the out house are boundary walls in my garden. She had no permission from me but I came home one day and she had directed her overflow pipe, pvc bath drainage pipe and guttering all on my wall, it upset me but I'm a wuss so didn't know how to deal with it. Have attached photo for ref. Weird garden boundaries as row of cottages used to belong to one family so odd division of gardens. 1) overflow pipe 2) guttering 3) bath drainage 4) her property 5)my garden.
So recently in another part of the garden she has now started cutting my hedge back and moving the boundary completely, this is a totally different arguement and I am getting a surveyor to sort this boundary line properly. But in trying to move the boundary she has massively damaged our hedge.... And I'm really pee'd of with her taking advantage and want all her crappy plastic pipes gone now (for additional information she didn't want a party wall agreement). So can I saw them off cap the pipe and return them to her???

She said she didn't want a party wall agreement as it wasn't necessary. Yes I did put the trellis there, it's hanging off nails already in the wall so not fixed and the hanging basket is hanging off a metal hook that's been there since before us. Have trained a plant up the wall though, should I do that??? I hadn't thought of my insurance, I just posted this on a garden forum and someone else suggested it, I will have to check.

You might be better putting posts in and have trellis as a fence in front of the wall rather than attached, which could hide the pipework too. However technically the pipes are trespassing over your property and what if there is a leak or blockage? Was the outbuilding previously an outdoor loo or washhouse?

@Slingsanderrors yes, webbed toe territory! 😄

What pipe are you thinking of capping off, the black guttering would just fill up and overflow into your garden without the pipe. Do you know who owns that wall.

I have an 18thC property, in a terrace and there are issues which we mostly solve amicably. Fortunately the responsibility for the shared drains is the water company's. Heaven only knows what the cost of 3 days full time pump and jet tanker , digging and repairing the pipe under the ndn's House, repairing the damage, hotel costs and a manhole for future access was.

As @12b2 says check the legal cover on your household policy as this has occurred since you bought the property. All the pipes for the macerator, water and drainage should be on the inside due to frozen pipes in the winter, and there shouldn't be an A framed roof causing drainage to go into ndn s property. There has been no planning permission nor does there appear to have been building regs.

OP It's not up to your ndn to decide whether to go for party wall agreements. However she is responsible for your surveyor's costs and you are entitled to have your own. But this sounds like a bodged job to me. Good luck, keep us updated on your progress.