Soldato
I've just been quoted £211 by Aveon, so will see what other quotes I can get.
I can drill holes and fairly decent at DIY, I wall mounted my tv when I moved in, but I just feel this is going to be a little more difficult, and as it's the living room, any shoddy work will be seen by guests?
It's really quite simple. As long as you can use a drill and tape measure/spirit level to ensure you put the brackets on straight you'll be fine. The screws are hidden by the actual blind anyway.
I did by myself on ~12 windows and the hardest part was man-handling the blinds, but if you get someone to help it's dead easy.
I bought all mine from https://www.blinds-2go.co.uk - great service. For the size you want vertical blinds are about £130.