That's awful!
That Zinwell LNB does have a pull down rain cover. However, it doesn't pull down over the entire F connector (it leaves about 5mm exposed at the bottom). There is a modified version now which does cover the entire F connector.
The amalgamating tape has been applied extremely poorly indeed. The tape should be stretched during application so that when applied, it effectively welds itself to itself. What you've got there isn't watertight.
The cabling is awful. No need for three clips on the horizontal run from the dish. The radius in the first bend doesn't need to be that big and just looks sloppy. The radius of the second bend is far too tight.
I personally like cable drops behind drain pipes but it should be taught and cable tied. That's just hanging loose and looks crap.
Horizontally, IMHO 450mm between clips isn't too bad. I personally clip slightly closer though, roughly every 2.5 bricks, but usually into the horizontal mortar line rather than the verticals as the vertical lines are often hollow and don't hold the clips too well. I always clip with the nails in the same orientation in case of future requirements to run n additional cable alongside the existing cable.
With regards to the entry hole. Standard practice is to drill from inside out. If you drill outside in you're guaranteed to blow plaster. He should have taken hammer off for the last half inch or so though, that would've prevented the brick blowing. Leaving hammer on is the lazy route - quicker must almost guaranteed to blow brick.
How much did you pay for installation and did you arrange it via Argos at time of purchase or did you contact the installer directly?