I rent a 2 bed flat in London for £2600 pcm with my friend

I rent a 2 bed flat in London for £2600 pcm with my friend which has a private balcony and a communal roof terrace. I was told a few months back that some essential building maintenance needed to be done at some point and during this time the roof terrace would be inaccessible. This was disappointing as this was one of the main reasons I took the flat but I agreed with the landlord a £200 pcm rental deduction as compensation while the weather is good. I have since been told that the builders now require my private balcony for doing the works. This involves erecting scaffolding and screens (that will block a huge amount of light to the flat and taking over my balcony with scaffolding and building materials. I have also spent all summer establishing a balcony garden at a cost of over £1000 for plants, planters and materials and a huge amount of hours invested into establishing it. I have been told all of this will have to be moved to the garden below. I am firstly upset at having spent so much time establishing the balcony only to see it all taken away, secondly concerned that the move will cause some of the plants to die from the trauma and also from the lack of light down in the garden and lack of support to grow against (they are mostly climbers), thirdly because I use that balcony every single evening to relax in and the outdoor space was a key factor for me in choosing this flat and this will now be unable to be used for the next 2-3 months. I do not know what to do.