I think this piece is quite lovely. It appears that your couch and chairs have dark wood so I would be tempted to stain or paint the buffet to match these items. Changing the large modern handles to smaller antique ones might help to make it less bulky looking and tie in with the other items in your room.. I like the idea of putting a mirror in the upper door, however much as I like the criss cross effect in the sample pictures, adding more detail may conflict with the curves in your sofa and chairs. You could look for a decorative detail that has more subtle style. As for placement, it might go on the short wall where you have a bench or even on the wall where you have your table with two chairs, one on each side to balance the look.

what colour on walls if whole cupboard is of dark purple

A combination of Offwhite, Beige Upholstery and dark shades of wood would look good. Provided you keep the wood minimal . The floor can also be a similar shade of wood . Remember whatever you do, make it look rich and elegant, only then will you be able to pull this look off. I am assuming the your ceiling is considerably high as well. Paint the walls and ceiling in offwhite shades with only the feature wall grey

Hi Reena, This looks like it needs a in-person discussion but nature wallpapers are not all that bad an option BUT! careful while you choose so it doesn't like 'fake'. Here, i will attach once image where it worked well: But it can also look bad and too fake if you make the wrong choice: You see the difference in feeling imparted? We can make it work by ensuring its in alignment with the colours you choose for the room and other add-ons. If you can share more details on what you are looking out to buy etc i can help you, UNLESS you want to take an easy road and get a consult with us, let our experts tell you how we can incorporate this into your room; because it looks like this will be much easier with an in person meeting. Also, I would like to note here that we own a great range of wall coverings & have our own expert interior designers to help you! https://www.atominteriors.com/swatchbook/wall-coverings.html Do inform if you would like a consultation, else share your doubts here! Will be happy to help! :) ATOM Interiors, Bangalore kirti@atominteriors.com