1. Can the landlord refuse to new tenant and force us continue to pay rent?
No. The Landlord has a duty to mitigate any loss. So if you are advertising the flat, that is fine.
2. Can the landlord refuse to let us advertising the flat? (we are currently paying the rent for the flat)
No. The Landlord saying that it devalues the flat is ridiculous, it makes no sense whatsoever. The Landlord can not refuse to let you advertise it.
I'm trying to figure out a way to negotiate with the landlord. We have offered to use our deposit (GBP 3300) to offset the rental liability, but got rejected. I'm going to discuss with the landlord again regarding additional compensation to offset the rental liability. But before that, I need to know the following:
3. If I stop the monthly payment (GBP 2400) starting from Feb, what's going to happen? My understanding is the landlord can only start suiting us at the end of our contract (June 30, 2018), and the landlord can only claim the amount minus the rental payment from new tenant (if the flat is rent out before June 30, 2018) minus our deposit (GBP 3300). Is this understanding correct?
4. If after June 30, 2018, the landlord decides to chase the payment, can he chase the payment internationally (my partner holds a Swiss passport and I hold a Hong Kong passport )? If yes, is there a minimum amount to enable him to chase rental payment internationally?
In reality no. It if was a country within the EU, then he could get a CCJ over here and then enforce it within the EU. He can't do this outside the EU as it is so much harder.
5. what other consequences should we consider if we stop the payment from next month?
That is it - all he can do is try and pursue you for lost rent. I also would not expect a reference from him!
6. What are the best actions we could do at this moment?
Stop paying if you are going to be going abroad. It makes no sense and it will save you money.
The Landlord is not being reasonable by trying to stop you advertise, so why should you be in paying the rent?
Can I clarify anything for you about this today, please?
not, I would appreciate a 5-star rating for my answer. If you need anything further I am available for a follow up at no extra cost.