Si, I feel for you. When I first got a Freesat box back in 2009, it was my first experience with satellite (to this day, I refuse to put more money into the Murdoch coffers!) and after getting a couple of very high quotes for fitting and cabling the dish, I decided to go down the DIY route after much deliberation. Although not a complete numpty, I am no technical genius either but in the end, I decided to take the plunge and bought a cheap dish, cable and quad LNB kit from Amazon for £40 along with a 'Satellite Finder' (made by Konig) for another £8. Having done a bit of research on line, I took a compass fix on a couple of dishes on neighbours houses so that I would know the general direction that the dish should point and after that all I had to do was fix it to the wall and fine tune the direction using the satellite finder. Luckily, the wall had already been drilled by the previous owners for their satellite cable and so all I had to do was get the cable through the hole which was already in the right place. Five years on, things still work so I can't have done much wrong.
Trust me, if I can do the job, anybody should be able to, particularly a so called professional, and unless the TV really is faulty it should all be relatively easy to fix.
As I said earlier, I went through a process of elimination and concluded that my solution to add dedicated cabling for the TV rather than use the LNB passthrough in the Humax box and I am about to order it on line. Hopefully this task will be as simple as I think it will be!
Hope you get things sorted to your satisfaction. Let us know how you get on. I am waiting to get a bit mnore experience with the TV under my belt before publishing any further comments on it but my initial reactions are very good indeed. Regards, Ayjaycee