So would a 3.2m meter dish but it's pointless for Sky.
The problem with Sky installations is they are installed by the Sky blokes (or some people DIY) with the crappy little bleeper signal testers and don't have enough rain fade margin.
All these crappy testers do is align the dish for maximum signal. But there's a lot more to it than that. How can you possibly set the LNB skew or check the bit error rate with one of those? You can't is the answer.
This means that every time we get rain a lot of people have problems with Sky reception.
Signal strength isn't as important as signal quality, so it's critical the skew is set correctly even in a domestic installation.
An 80cm dish for Sky reception is pointless. Yes it will work fine, but it's completely over the top unless you are talking about a large SMATV communal system where you want the increased C/N ratio to carry through the system.