no, the legislature is not a jury. they have completely separate purposes and rationales of composition
a jury has random people because it is people, not representatives, that should decide innocence - the decision of innocence (or guilty) doesn't create laws like parliaments do. if you had a jury that was composed of all sections of political society, you wouldn't get unbiased justice but you'd get ochlocracy. that's why it has to be unanimous - because the jurists must reach come kind of neutrality and consensus together, not just via a bare majority. if you had jury-like members in an upper chamber, you could essentially, from time to time, be making laws that NOBODY likes just because you happen to have a day where all the jurists were radicals of some nature. how is that appropriate? why should majoritarian legislation be down to pure luck?! it wouldn't be a neutral consensus because it wouldn't have to be unanimous!
such an idea is totally ridiculous. I hate when people bring this one up because it doesn't appreciate the differences between these two branches. in my opinion, the house of lords is totally useless as it is. it is powerless and has absolutely no constitutional role. it is 75% party political so it is not an effective non-partisan check on party officials and their ambitions. we aren't a federal state so why would we need an upper chamber for such a parliament then if our parliament doesn't perform a check on the power of the government? and if it ever does, it's incredibly minor and more thratrical than substantial. I *do* happen to think we should become a federal state, and therefore, have an *elected* chamber, but I just have such bare faith in politic(ian)s these days that I am never going to hold my breath for that.