Hi John and welcome!
I live in Munich too, and sadly the 80cm dish is too small here. I started with that. I moved up to the Gibertini 100cm and I now get 75 to 80% on the main BBC channels. I've been thinking of getting the 125cm, but after changing things a bit, the 100 seems to be fine.
I followed the tuning guides here (finding the strong signal, then switching to the weaker one to fine tune) and with the great help in my post:
Can't find 28.2 from Munich
Nice part of this dish is that it picks up great signals on the other main sats too.
If you want any ideas/help on reception from Munich, or a very helpful local source, feel free to ask!