Mr. Thatcher is such a liberal that his policies can’t be reconciled between him and

a genuinely conservative UK politician. Plus he doesn’t seem to care that much about politics?

The use of plenty signifies sufficiency or selflessness.

A lot connotes many (friends) and much (money) respectively and indicates the writer may at some point may need more of the same in life, but not necessarily.

Who has the best quantity of either or an author? To me, the second also may indicate more of a boastful attitude than the first, to which that still may apply.