Neighbours extension straddling Party Wall Line

[RandomTask23]

Hi,
I'm looking for some advice please.

I live in a semi-detached house and last year my neighbour and I both separately got planning permission for rear extensions that would share the party wall line. Theirs is a full-width rear extension and ours is a smaller half-width rear extension that fills in the gap up to the party line left by a previous L-shape rear extension (circa 1970s)

Since then our circumstances have changed and unfortunately, we can no longer do our extension. I verbally told our neighbour this about a month or two ago.

Our neighbour popped round yesterday to say they are starting work today! Firstly I thought they had to give me 1 or 2 months notice through a party wall agreement. Am I right? When we last spoke in December, they had only just appointed a builder with no planned start date.

Secondly, do I have any right to request that the neighbour's extension now remains wholly on their own land (even though planning permission has it straddling the boundary)? I am concerned that encroachment will cause issues if/when we come to sell our property. Plus the further into our land it comes, the more light it will block into our existing rear room (in the "L"). The light wouldn't have been an issue if we had done our own extension.

We currently get on well with our neighbours so I am hoping to work it out...I'm just not sure on what my rights are at this stage.

Many Thanks.

 

[Mottie]

If you were planning to share a wall, surely you’re only talking a little over a bricks width of encroachment? If I’ve got that right, I’d be tempted to leave it - at least if you wanted to build in the future, you have one wall already done, wouldn’t you? If you forced them to change plans, could they mess you about in the future if you wanted to build?

 

[^woody^]

You've agreed to this already, the PW Act does not apply nor the notice periods. And you really should not be stating that it will be encroaching, as that's completely wrong.

Yes you could ask for the wall to now be built wholly on their side, and you need to tell them sooner not later. There may be a cost to that, and it's up to you if you would like to contribute to it.