Neighbours building

[Talkingpoints]

Bit of a different story from neighbours being unreasonable - but not sure how I should approach this:

So generally I get on well with my neighbours across the road from me. Not to entirely hold a conversion, but we say hello when we see each other. One day as I looked out the window I noticed that he had completely knocked down the side extension to his house, it looked horrible. Next thing, we noticed that there was a council notice outside of his house for him to build a 2 storey extension - great I thought! Well it seems as if the building has completed now and the "extension" he has built looks terrible. It looks like a shanty. Basically in the back of his garden he has built a wooden structure and tacked on a plastic Tarp as a door. The bit of house he originally knocked down is now a shoddy bit of wood with a tin roof. It looks worse than what it did before. The neighbours next to him already don't do any upkeep on their house and now this makes the area look worse. Ultimately I'm worried about my property value.
Is there anything I can do to make my neighbour...finish his extension? I'm sure the council wouldn't have okayed this.

Thanks.

Planning permission is just permission to start the works, there's no issue with not finishing. You could just build the shell and leave it as long as it's not a danger.
Even if there's a planning application, property value is not a relevant consideration.
Plastic tarp is likely to be considered temporary, but even without a tarp it wouldn't really look much better. You can't force someone to add a door.
There may be building regs issues especially if it's open to the rest of the house, but those are not relevant to you, they mainly relate to the health and safety and efficiency etc of the building.

Look at the council web site at what was actually applied for, you should be able to open the drawings and description. If it doesn't match then you can report to the council, but ultimately it's up to them to decide what to do.

Good luck!

Thanks for the information about looking for what was applied for - it is absolutely nothing like what they have built! Will try to take this further with council.