I have installed one myself once, and it can be a very complicated process. I suppose it is easier if you are replacing an old one for a new one since there will already be various parts in place that can be reused. But I tried doing it from scratch. And while it turned out ok eventually, it took a full day dealing with complicated tutorials, and I still had to tweak my installation several times after I was “done”.
Your main concerns when doing the installation, yourself will be finding the best place in the house to install the unit and making sure the wall in question is structurally sound enough to support the weight. And at the end of the day, there is so much that can go wrong with the whole process that the DIY approach is hardly worth it. I recommend you go with an air conditioning Tunbridge Wells company like https://www.teklima.co.uk/air-conditioning-tunbridge-wells.htm for the installation instead. If you can afford it.
