Designing/decorating the rooms in our house (UK)

Hi there!
We bought our house last year here in the UK and we are now at the stage when we want to start decorating it. The problem is, we are really bad at interior design and getting things to 'match' so we are looking for some professional help.

The idea is that the interior designer we choose will be able to work around our current house and give us their take of how they would decorate it. For example we already have a sofa, we don't necessarily want to be told to throw it away, but rather try and make the space look nice with it there. Although we are flexible. We would be looking for a total picture of the room, from colour of the walls, artwork, rugs, vases, etc.
The interior designer also needs to be able to take into consideration functionality of the room, cost, and style.

We will only consider designers that have some sort of portfolio or social media showcasing work, ideally UK based homes. We would love to see some sort of 2d or 3d rendering options which will then allow us to start making them a reality.

We will be looking to do this for every single room of the house but we want to start with the living room.
In summary, we are hoping to 'Pinterest-ify' our home and need some help!

Budget flexible, especially if previous work that's showcased is of high standards!
Thank you,
Irene