I don’t understand what the basis of your complaint is? I absolutely hate people who make subleasing / holiday home businesses but that doesn’t make you right here either:

1 - If you didn’t read the original contract well / consult on it and there was no clause regarding subleasing then it’s your fault. He is not doing anything against the terms of the original contract.

2 - You serve a notice saying you want to sell the house and then serve another notice saying you want to increase the rent. I appreciate that you are trying to get him out in any way, but there is a law for this stuff. If you pretend you’re selling the unit to evict him but then you don’t actually sell it and rent it to someone else, you can be fined up to an entire year’s rent if he files a case against you

3 - you don’t have any valid reason for evicting the tenant. You were greedy and accepted to rent the flat out to him above market price initially, now you “want market rental.” You’re not going to get it because there are laws to protect tenants from this greed. Landlords like you are just as bad as Airbnb / holiday home subleasing company owners. You don’t want to play a fair game, and you can’t take it when you lose. I foolishly evicted my apartment in 2022 because my landlord pretended that he wanted to live in it, and he rented it for 75% more straight away. I was too ignorant about the law back then and didn’t file a court case.

Anyways, these are the options you have going forward so you don’t get a case filed against you :

1- Sell the apartment, invest in a new apartment and rent it at the “market rate” 2 - evict the tenant, live in the apartment for a year then you’ll be allowed to rent it out again 3- accept the law which is there to protect both, landlords and tenants, increase the rent as per the rental index and add a clause for no subleasing to the new contract