To answer your question about different types of dish
I have the Maxview Semitronic which is a crank up non self seeker and has been DIY fitted
It has the advantage that all the wiring to the Tv and digi box are set up before leaving home and its just a matter of chosing a south facing pitch and using a meter inside the van out of the weather finding the satellite
Its not as convenient as the dome type as the crank up has to be retracted in high winds and you have to find the satellite rather than it doing it automatically
I also carry a small tripod and dish for the rare occasion that a suitable pitch is not available
Its happened 3 times in 500 camping days so far
It involves drilling a 50mm hole in the van roof which is covered by a plate,rubber ring and sealant and its now on the 4th van with absolutely no sign of water ingress when removal was made
Road Pro and Conrad Anderson do a good job as does Leisure Power of Warrington
This is not to decry previous valid posts but just to tell it how I have found it